Yesterday, there were four times as many ducks as sheep on a farm. Today, 21 ducks are sold. There are twice as many sheep now. Find the total number of sheep and ducks on the farm yesterday.
| |
Ducks |
Sheep |
Total |
| Before |
4x2 =
8 u |
1x2 =
2 u |
10 u |
| Change |
- 21 |
|
|
| After |
1 u |
2 u |
|
The number of sheep at first and in the end remains unchanged. Make the number of sheep the same. LCM of 1 and 2 is 2.
Number of ducks sold
= 8 u - 1 u
= 7 u
7 u = 21
1 u = 21 ÷ 7 = 3
Total number of sheep and ducks yesterday
= 8 u + 2 u
= 10 u
= 10 x 3
= 30
Answer(s): 30
