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USA TODAY® Related Activities
A
Draining Experience
Teacher
Notes:
· As an extension,
have students write and solve their own problem similar to the problems in this
activity.
· Make sure
students understand that the pool is empty on the half-hour and not the hour.
Ask them to share their strategies for finding the exact time. The problem in
Wrapping Up the Activity also does not have an answer that is a whole hour.
Procedure
for the Activity
Answers:
Step 1 3900 m3
Step
2 The amount of
water drained by Drain 1 in one hour is 255 m3. The amount of water
drained by Drain 2 in one hour is 345 m3.
Step 3
Time |
Amount
Drained by Drain 1
in
One Hour (m3) |
Amount
Drained by Drain 2
in
One Hour (m3) |
Total
Amount Drained by Both Drains (m3) |
Amount
of Water Left in the Pool
(m3) |
8
A.M. |
0 |
0 |
0 |
3900 |
9
A.M. |
4.25(60)
= 255 |
5.75(60)
= 345 |
255
+ 345 = 600 |
3900
– 600 = 3300 |
10
A.M. |
255 |
345 |
600 |
3300
– 600 = 2700 |
11
A.M. |
255 |
345 |
600 |
2700
– 600 = 2100 |
noon |
255 |
345 |
600 |
2100
– 600 = 1500 |
1
P.M. |
255 |
345 |
600 |
1500
– 600 = 900 |
2
P.M. |
255 |
345 |
600 |
900
– 600 = 300 |
3
P.M. |
255 |
345 |
600 |
300
– 600 = –300 |
4
P.M. |
255 |
345 |
600 |
|
5
P.M. |
255 |
345 |
600 |
|
6
P.M. |
255 |
345 |
600 |
|
Step 4 The pool will be empty at 2:30 P.M. The pool only has 300 m3 of water left at 2 P.M. That water can drain out in one-half hour, so that is 2:30 P.M.
Step 5 Sample answer: Since 600 m3 of water drains per hour, you can divide 3900 by 600 and get 6.5. 6.5 hours
after 8 A.M. is 2:30 P.M.
Wrapping
Up the Activity
Time |
Amount
Filled
by
Hose 1 in
One
Hour (m3) |
Amount
Filled
by
Hose 2 in
One
Hour (m3) |
Amount
Filled
by
Hose 3 in
One
Hour (m3) |
Total
Amount
Filled
by
All
Hoses (m3) |
Amount
of Water in the Pool
(m3) |
6
A.M. |
0 |
|
0 |
0 |
0 |
7
A.M. |
2.25(60)
= 135 |
2.5(60)
= 150 |
3.25(60)
= 195 |
135
+ 150 + 195 = 480 |
480
m3 |
8
A.M. |
135 |
150 |
195 |
480 |
480
+ 480 = 960 |
9
A.M. |
135 |
150 |
195 |
480 |
960
+ 480 = 1440 |
10
A.M. |
135 |
150 |
195 |
480 |
1440
+ 480 = 1920 |
11
A.M. |
135 |
150 |
195 |
480 |
1920
+ 480 = 2400 |
noon |
135 |
150 |
195 |
480 |
2400
+ 480 = 2880 |
1
P.M. |
135 |
150 |
195 |
480 |
2880
+ 480 = 3360 |
2
P.M. |
135 |
150 |
195 |
480 |
3360
+ 480 = 3840 |
3 P.M. |
135 |
150 |
195 |
480 |
3840
+ 480 = 4320 |
The pool is almost full at 2 P.M. There are 3900 – 3840 = 60 gallons left. That amount of water will take (60 ÷ 480)
= 0.125 of an hour. 0.125 of an hour is 0.125(60) = 7.5 minutes. The pool will
be full at about 2:08 P.M. |
Test Practice