There are 3 times as many cows as ducks.
There are 140 legs altogether.
- Find the number of animals.
- Find the number of more cows than ducks.
- Find the number of more cows' legs than ducks' legs.
| |
Cows |
Ducks |
Total |
Number
(Number of animals) |
3 u |
1 u |
4 u |
Value
(Number of legs) |
4 |
2 |
|
Total value
(Total number of legs) |
3 x 4 =
12 u |
1 x 2 =
2 u |
14 u |
(a)
Let the number of ducks be 1 u.
Number of cows = 3 u
Number of cows' legs = 4 x 3 u = 12 u
Number of ducks' legs = 2 x 1 u = 2 u
Total number of legs = 12 u + 2 u = 14 u
14 u = 140
1 u = 140 ÷ 14 = 10
Number of animals
= 3 u + 1 u
= 4 u
= 4 x 10
= 40
(b)
Number of more cows than ducks
= 3 u - 1 u
= 2 u
= 2 x 10
= 20
(c)
Number of more cows' legs than ducks' legs
= 12 u - 2 u
= 10 u
= 10 x 10
= 100
Answer(s): (a) 40; (b) 20; (c) 100
