# SAT Math - Question of the day - 8 Nov 2016

A farm has birds and dogs.If there are 120 heads and 300 feets. How many birds are there?

Option:

a)  50

b)  60

c)  70

d)  90

Solution:

A bird has 2 feets and 1 head.

A dog  has 4 feets and 1 head.

Let's assume the number of dogs to be y.

Let's assume the number of birds to be x.

Total number of heads = 120

Total number of heads of birds = (1) (x) = x

Total number of heads of dogs = (1) (y) = y

x + y = 120

Total number of legs = 300

Total number of legs of birds = (2) (x) = 2x

Total number of heads of dogs = (4) (y) = 4y

2x + 4y = 300

Solving the both equations

x = 90

Hence, choice D is correct.

Try to solve this question on your own! Do post your comments and solutions in the comment section below.

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