The correct option is B 2 : 3
Given,
Number of mangoes eaten by Amit in 20 mins = 10
∴ In 1 minute, he'll eat =1020 = 12 mangoes
Again,
Number of mangoes eaten by Raj in 15 mins = 5
∴ In 1 minute, he'll eat =515 = 13 mangoes
Therefore, the ratio of number of mangoes eaten by Raj to that of Amit is
=13:12
or, 1312 = 23
or, 2 : 3