The weights of three boys are in the ratio 4 : 5 : 6. If the sum of the weights of the heaviest and the lightest boy is 45 kg more than the weight of the third boy, what is the weight of the lightest boy?	Choose the most appropriate option:
A) 87 kg	B) 36 kg	C) 98 kg	D) 65 kg	E) 87 kg
Let the weights of the three boys be 4k, 5k and 6k respectively.   4k + 6k = 5k + 45   =&gt; 5k = 45 =&gt; k = 9   Therefore the weight of the lightest boy   = 4k = 4(9) = 36 kg.   Answer:36 kg
<result>B</result>
The weights of three boys are in the ratio 4 : 5 : 6. If the sum of the weights of the heaviest and the lightest boy is 45 kg more than the weight of the third boy, what is the weight of the lightest boy?