At an educational trip of a school ratio of boys to girls students was 4/5. how many students were on the tour?

Data is insufficient for this problem. But we can find the answer from the options. As 4 + 5 = 9, So answer should be multiple of 9 to fullfil the condition of 4/5 ratio..

The average weight of 16 boys in a class is 50.25 kg and that of the remaining 8 boys is 45.15 kg.Find the average weights of all the boys in the class.

! !In this question weighted average is calculated rather than simple average! !(50.25*16 + 45.15*8)/(16+8) = 48.55.

Price of a mobile phone is Rs. 8,000. A man has enough money to purchase 3 mobiles. How many mobile can he purchase if the price is reduced by Rs. 2000?

Minimum amount of money that he has = 8,000 * 3 = 24,000! !If price is reduced to 6,000, he can purchase 24,000/6,000 = 4.

A cigarette case is full of cigars and cigarettes, probability of a cigarette is 8/15. What is the ratio of cigars to cigarettes.

In 15 cigars and cigarettes there are 8 cigarettes So ratio between cigars and cigarettes is 8/7. Which means there are 8 cigarettes and 7 cigars..

35 Kg of spinach costs Rs. 28. How many Kg of spinach can be bought for Rs. 16?

Amount of spinach which can be bought in Rs. 28 = 35 kg! !Amount of spinach which can be bought in Rs. 1 = 35/28 = 5/4 Kg! !Amount of spinach which can be bought in Rs. 16 =(5/4)*16 = 20 Kg.

In the first 10 overs of a cricket game the run rate was only 3.2 What should be the run rate in the remaining 40 overs to reach the target of 282?

3.2 * 10 = 32! !After 10 overs score is 32.! !Remaining score = 282 - 32 = 250! !Required rate = 250 / 40 = 6.25 runs/over.

If the average marks of three batches of 55, 60 and 45 students respectively is 50, 55, 60, what is the average marks of all the students?

Weighted average will be more close to the average of that batch which has maximum number of students so aanswer is 54.68! !If you want to calculate it by formula then solution is! !(55*50 + 60*55 + 45*60)/(55 + 60 + 45) = 54.68.

At a particular time shadow of a pole 40m long is measured to be 30m. If the length of a plaza is 200m then how long would the shadow be at about the same time?

Shadow of 40m pole = 30m! !Shadow of 1m pole = 30/40m! !Shadow of 200m plaza = (30/40)*200 = 150m.