Page 167 - NUMINO Challenge_D2
P. 167
Answer
Key
14 Solving Problems Using Ratio p.120~p.121 Problem solving
Example 25, 6,000 10,000 1 Since is 250% of , is 2.5 times . If is 2
16,000, 15,000 1,000, loss
then becomes 5, and since the double of is
4, then the double of is 4 100 80% of .
5
TryItAgain Since 50% more math books were sold than 2 Since the number of bottles of water at the start
English books, it means that when 100
English books were sold, 150 math books occupied 20% of the 250 bottles, there were
were sold. From the total number of 250 20 250 50 bottles of water and 250 50
100
books, the ratio of selling math books is 200 bottles of juice. After some bottles of juice
150 0.6. Therefore, when a total of were sold, the number of bottles of water
250
occupied 25% of the remaining bottles, which
1,000 English and math books were sold in
one week, the number of math books sold means that 50 bottles are now occupying 25% of
was 1,000 0.6 600 books. the total. There are 50 4 200 bottles in total
and 200 50 150 bottles of juice left.
Example Number of times at bat Therefore, 200 150 50 bottles of juice were
34
17, 11, 187 sold.
187
Type 14-2 The Baseball Batting Champion p.124~p.125
TryItAgain Since (Batting Average) (Number of Hits) 1 Since 0.625 Number of Hits 32, the number
(Number of Times at Bat), the batting of hits Chris made is 20. Since 0.625 Number
average of Ryan is 90 250 0.36. of Hits 24, the number of hits Jeff made is 15.
Type 14-1 Change in Weights p.122~p.123 2 The number of times at bat of Chris until the 7th
round is 32 4 36, and the number of hits is 20.
1 Since of the 5 kg of pumpkin, 90% was water, The number of times at bat for Jeff until the 7th
the remaining 10% is the part that doesn't round is 24 4 28, and the number of hits is 15.
include the water. Therefore, the weight of the
pumpkin excluding the water is 3 Since Batting Average of Chris 20 0.5555...,
5 0.1 0.5 kg. 36
2 Since 80% of the pumpkin is water, the part of when you round off the number to three decimal
the pumpkin that doesn't include the water
occupies 100 80 20% of the pumpkin. places, you get 0.556, which is .556. Since
3 Since the part that doesn't include the water Batting Average of Jeff 15 0.5357..., when
occupies 20% of the entire pumpkin and weighs 28
0.5 kg, the weight of the water that occupies
80% of the pumpkin is 0.5 4 2 kg. Therefore, you round off the number to three decimal
the weight of the pumpkin is 0.5 2 2.5 kg.
places, you get 0.536, which is .536. Therefore,
Chris will be the batting champion.
NUMINO Challenge D2
Key
14 Solving Problems Using Ratio p.120~p.121 Problem solving
Example 25, 6,000 10,000 1 Since is 250% of , is 2.5 times . If is 2
16,000, 15,000 1,000, loss
then becomes 5, and since the double of is
4, then the double of is 4 100 80% of .
5
TryItAgain Since 50% more math books were sold than 2 Since the number of bottles of water at the start
English books, it means that when 100
English books were sold, 150 math books occupied 20% of the 250 bottles, there were
were sold. From the total number of 250 20 250 50 bottles of water and 250 50
100
books, the ratio of selling math books is 200 bottles of juice. After some bottles of juice
150 0.6. Therefore, when a total of were sold, the number of bottles of water
250
occupied 25% of the remaining bottles, which
1,000 English and math books were sold in
one week, the number of math books sold means that 50 bottles are now occupying 25% of
was 1,000 0.6 600 books. the total. There are 50 4 200 bottles in total
and 200 50 150 bottles of juice left.
Example Number of times at bat Therefore, 200 150 50 bottles of juice were
34
17, 11, 187 sold.
187
Type 14-2 The Baseball Batting Champion p.124~p.125
TryItAgain Since (Batting Average) (Number of Hits) 1 Since 0.625 Number of Hits 32, the number
(Number of Times at Bat), the batting of hits Chris made is 20. Since 0.625 Number
average of Ryan is 90 250 0.36. of Hits 24, the number of hits Jeff made is 15.
Type 14-1 Change in Weights p.122~p.123 2 The number of times at bat of Chris until the 7th
round is 32 4 36, and the number of hits is 20.
1 Since of the 5 kg of pumpkin, 90% was water, The number of times at bat for Jeff until the 7th
the remaining 10% is the part that doesn't round is 24 4 28, and the number of hits is 15.
include the water. Therefore, the weight of the
pumpkin excluding the water is 3 Since Batting Average of Chris 20 0.5555...,
5 0.1 0.5 kg. 36
2 Since 80% of the pumpkin is water, the part of when you round off the number to three decimal
the pumpkin that doesn't include the water
occupies 100 80 20% of the pumpkin. places, you get 0.556, which is .556. Since
3 Since the part that doesn't include the water Batting Average of Jeff 15 0.5357..., when
occupies 20% of the entire pumpkin and weighs 28
0.5 kg, the weight of the water that occupies
80% of the pumpkin is 0.5 4 2 kg. Therefore, you round off the number to three decimal
the weight of the pumpkin is 0.5 2 2.5 kg.
places, you get 0.536, which is .536. Therefore,
Chris will be the batting champion.
NUMINO Challenge D2
