There are 3 times as many dogs as parrots.
There are 70 legs altogether.
- Find the number of animals.
- Find the number of more dogs than parrots.
- How many less parrots' legs are there than dogs' legs
| |
Dogs |
Parrots |
Total |
Difference |
| Number (Animals) |
3 u |
1 u |
4 u |
2 u |
| Value (Legs) |
4 |
2 |
|
|
| Total value (Total legs) |
12 u |
2 u |
14 u |
10 u |
Choose the animal type with a smaller number to be 1 u.
Let the number of parrots be 1 u.
Number of parrots = 1 u
Number of dogs = 3 u
Number of parrots' legs = 2 x 1 u = 2 u
Number of dogs' legs = 4 x 3 u = 12 u
Total number of legs
= 12 u + 2 u
= 14 u
14 u = 70
1 u = 70 ÷ 14 = 5
(a)
Number of animals
= 3 u + 1 u
= 4 u
= 4 x 5
= 20
(b)
Number of more dogs than parrots
= 3 u - 1 u
= 2 u
= 2 x 5
= 10
(c)
Number of less parrots' legs than dogs' legs
= 12 u - 2 u
= 10 u
= 10 x 5 = 50
Answer(s): (a) 20; (b) 10; (c) 50
