Some ducks and pigs are in a farm. These animals have a total of 23 heads and 70 legs.
- How many pigs are there?
- How many ducks are there?
Number of pigs |
Number of pigs' legs |
Number of ducks |
Number of ducks' legs |
Total legs |
23
|
23 x 4 = 92 |
0
|
0
|
92 |
22
|
22 x 4 = 88 |
1
|
1 x 2 = 2 |
90
|
12 |
12 x 4 = 48 |
11
|
11 x 2 = 22 |
70
|
Number of legs if all are pigs
= 23 x 4
= 92
Big difference between the number of legs of the pigs and the ducks
= 92 - 70
= 22
Small difference between the number of legs of one pig and one duck
= 4 - 2
= 2
Numbers of ducks
= 22 ÷ 2
= 11
(b)
Number of pigs
= 23 - 11
= 12
Answer(s): (a) 11; (b) 12