There are 3 times as many donkeys as ducks.
There are 210 legs altogether.
- Find the number of animals.
- Find the number of less ducks than donkeys.
- Find the number of less ducks' legs than donkeys' legs.
|
Donkeys |
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 donkeys = 3 u
Number of donkeys' 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 = 210
1 u = 210 ÷ 14 = 15
Number of animals
= 3 u + 1 u
= 4 u
= 4 x 15
= 60
(b)
Number of less ducks than donkeys
= 3 u - 1 u
= 2 u
= 2 x 15
= 30
(c)
Number of less ducks' legs than donkeys' legs
= 12 u - 2 u
= 10 u
= 10 x 15
= 150
Answer(s): (a) 60; (b) 30; (c) 150