Page 132 - NUMINO Challenge_B1
P. 132
Basic Concepts Broken Clock
There is an analog clock that runs 5 minutes faster each day. It is set at exactly
noon today. The clock will be 5 minutes faster after one day, 10 minutes faster
after two days, and 15 minutes faster after three days. Therefore, the difference
between the actual time and the time shown on the broken clock will also
increase by 5 minutes, 10 minutes, 15 minutes, and so on.
Today After a day After 2 days After 3 days After 4 days
Actual time 12:00 pm 12:00 pm 12:00 pm 12:00 pm 12:00 pm
12:00 pm 12:05 pm 12:10 pm 12:15 pm 12:20 pm
Time on The 5 minutes 10 minutes 15 minutes 20 minutes
Broken Clock 0
Difference
According to the rules shown above, when the difference between the actual
time and the time shown on the broken clock becomes 12 hours, the broken
clock shows the same time as the actual time for the first time.
Example A broken analog clock that runs 10 minutes faster each day is set
at exactly 12 pm today. After today, when will the broken clock tell
the correct time again? Specify the time and after how many days
from now.
Class Notes
Complete the table below.
Today After a day After 2 days After 3 days After 4 days After 5 days
Actual Time 12:00 pm 12:00 pm 12:00 pm 12:00 pm 12:00 pm 12:00 pm
Fast Time 12:00 pm
0
Difference
(minutes)
When the difference between the actual time and the time shown by the broken clock is
hours, the broken clock tells the same time as the actual time.
The difference between the actual time and the time shown by the broken clock is 10
minutes more a day. Since hours is equal to minutes, the broken clock
tells the correct time after days, at pm.
Try It Again A clock that runs 4 minutes faster each day is set at exactly 12 pm
today. After today, when will this clock tell the correct time again?
129Measurement
There is an analog clock that runs 5 minutes faster each day. It is set at exactly
noon today. The clock will be 5 minutes faster after one day, 10 minutes faster
after two days, and 15 minutes faster after three days. Therefore, the difference
between the actual time and the time shown on the broken clock will also
increase by 5 minutes, 10 minutes, 15 minutes, and so on.
Today After a day After 2 days After 3 days After 4 days
Actual time 12:00 pm 12:00 pm 12:00 pm 12:00 pm 12:00 pm
12:00 pm 12:05 pm 12:10 pm 12:15 pm 12:20 pm
Time on The 5 minutes 10 minutes 15 minutes 20 minutes
Broken Clock 0
Difference
According to the rules shown above, when the difference between the actual
time and the time shown on the broken clock becomes 12 hours, the broken
clock shows the same time as the actual time for the first time.
Example A broken analog clock that runs 10 minutes faster each day is set
at exactly 12 pm today. After today, when will the broken clock tell
the correct time again? Specify the time and after how many days
from now.
Class Notes
Complete the table below.
Today After a day After 2 days After 3 days After 4 days After 5 days
Actual Time 12:00 pm 12:00 pm 12:00 pm 12:00 pm 12:00 pm 12:00 pm
Fast Time 12:00 pm
0
Difference
(minutes)
When the difference between the actual time and the time shown by the broken clock is
hours, the broken clock tells the same time as the actual time.
The difference between the actual time and the time shown by the broken clock is 10
minutes more a day. Since hours is equal to minutes, the broken clock
tells the correct time after days, at pm.
Try It Again A clock that runs 4 minutes faster each day is set at exactly 12 pm
today. After today, when will this clock tell the correct time again?
129Measurement
