A fruit seller has a crate of apple containing 1 bruised apple for every 40 apples in the crate, If 3 out of every 4 bruised apples are considered unsaleable and there are 9 unsaleable apples in the crate, then how many apples are there in the crate?

Let total number of apples in the crate = a
Then, number of bruised apples = a/40 .
Number of unsaleable apples
since 4 bruise apples containing 3 unsaleable apples.
therefore 1 bruise apples will contain 3/4 unsaleable apples
hence a/40 bruise apples will contain 3/4 x a/40 unsaleable apples
= 3/4 x a/40 = 3a/160
According to the question.
3a/160 = 9
⇒ a = 9 x 160/3
a = 3 x 160 = 480