The ratio of A and B in an alloy is 2 : 5. If the alloy is made of only A and B, how much amount of B will be there in 210 kg of that alloy?

150 kg 135 kg 60 kg 180 kg

150 kg

A : B 2 :  5 ⇒ (2 + 5)units = 210 ⇒ 7 units = 210 ⇒ 1 unit = 30. ⇒ Amount of B in the alloy = 5 x 30 = 150 Kg.