There are 2 times as many dogs as ducks.
There are 80 legs altogether.
- Find the number of animals.
- Find the number of less dogs than ducks.
- How many more dogs' legs are there than ducks' legs?
| |
Dogs |
Ducks |
Total |
Difference |
| Number (Animals) |
2 u |
1 u |
3 u |
1 u |
| Value (Legs) |
4 |
2 |
|
|
| Total value (Total legs) |
8 u |
2 u |
10 u |
6 u |
$
Choose the animal type with a smaller number to be 1 u.
Let the number of ducks be 1 u.
Number of ducks = 1 u
Number of dogs = 2 u
Number of ducks' legs = 2 x 1 u = 2 u
Number of dogs' legs = 4 x 2 u = 8 u
Total number of legs
= 8 u + 2 u
= 10 u
10 u = 80
1 u = 80 ÷ 10 = 8
(a)
Number of animals
= 2 u + 1 u
= 3 u
= 3 x 8
= 24
(b)
Number of less dogs than ducks
= 2 u - 1 u
= 1 u
= 1 x 8
= 8
(c)
Number of more dogs' legs than ducks' legs
= 8 u - 2 u
= 6 u
= 6 x 8 = 48
Answer(s): (a) 24; (b) 8; (c) 48
