There are 3 times as many pigs as ducks.
There are 420 legs altogether.
- Find the number of animals.
- Find the number of less ducks than pigs.
- Find the number of less ducks' legs than pigs' legs.
| |
Pigs |
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 pigs = 3 u
Number of pigs' 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 = 420
1 u = 420 ÷ 14 = 30
Number of animals
= 3 u + 1 u
= 4 u
= 4 x 30
= 120
(b)
Number of less ducks than pigs
= 3 u - 1 u
= 2 u
= 2 x 30
= 60
(c)
Number of less ducks' legs than pigs' legs
= 12 u - 2 u
= 10 u
= 10 x 30
= 300
Answer(s): (a) 120; (b) 60; (c) 300
