A 28 B 40 C 20 D 100 number of red bric number of grey bric

A. 28

B. 40

C. 20

D. 100

number of red bric number of grey bric

Solution

let the number of red bricks be equal to R and number of Grey bricks be equal to G.

From question it is given that

number of red bricks/number of grey bricks =5/2

putting our denotions we get

R/G =5/2

or ,R/G=2.5

or , R=2.5G ---i

Now it says that there were 140 bricks in total.

i.e, Number of red bricks +number of grey bricks =140

or, R+G=140 --------ii

but R=2.5G

thus substituting the value of R in equation ii ,we get

2.5G+G=140

or, 3.5G=140

solving for G we get

G=40

Thus there were 40 grey bricks

Thus total number of red bricks =140-40 =100 .

Thus there were 100 red bricks.