Math Booster Ans Key

Answer Key Math Booster

Q.1 Is 881 is prime Number?

Ans: prime number

Q.2 Is 979 a prime Number?

Ans: not prime

Q.3 Which is greater: 4/5 or 6/23?

Ans: 4/15

Q.4 Which is greater: 13/15 or 20/23?

Ans: 20/23

Q.5 Number of numbers up to 500 which are divisible by 13?

Ans:23

Q.6 What is the number of prime factors in the expression (6)¹⁰ *(7)¹⁷ *(11)²⁷ ?  

Ans:64 

Q.7 A can do a piece of work in 12 days. B is 60% more efficient than A. Find the number of days B to the same piece of Work?

Ans: 7½ days

Q.8 A milkman adds 3 liters of water to 12 liters of milk and another 4 liters of water to 10 liters of milk. What is the ratio of the strengths of milk in the two mixtures?

Ans: 28:25 

Q.9 Two numbers are respectively 20% and 25% of a third number. What is percentage is the first of the second? 

Ans:80%

Q.10 A man loses 12½ % of his money and, after spending 70% of the remainder, he is left with Rs 210. How much had he at first? 

Ans: Rs 800 

Q.11 After deducting 10% from a certain sum, and then 20% from the remainder, there is Rs 3600 left. Find the original sum?

Ans:5000

Q.12 if the annual increase in the population of a town is 4% and the present number of people is 15,625 what will the population be in 3 years? 

Ans:17576

Q.13 The Average of 11 results is 30, that of the first five is 25 and that of the last five is 28. find the value of the 6th number? 

Ans:65

Q.14 The average of the first 61 natural numbers is? Ans :31

Q.15 A man drives to his office at 60 km/hr and returns home along the same route 30 km/hr. find the average speed? 

Ans: 40 km/hr

Q.16 The age of man is 4 times of his son. 5 years ago, the man was nine time as old as his son was at that time. What is the present age of the man? 

Ans:32 years

Q.17 A boy buys apples at 9 for Rs 16 and sells them at 11 for Rs 20. what does he gain or lose percent? Ans: 2 3/11 %. 

Q.18 A machine is sold for Rs 5060 at a gain of 10%. What would have been the gain or loss percent if it had been sold for Rs 4370.? 

Ans:loss 5%.

Q.19 A man lends Rs. 10000 in four parts. if he gets 8% on Rs 2000, 7 ½ % on rs. 4000 and 8 ½ % on Rs. 1400. what percent must he get for the remainder, if the average interest is 8.13%.? 

Ans:9%

Q.20 The compound interest on a certain sum for 2 years is rs 40.80 and simple interest in Rs 40. find the rate per annum and the sum.? 

Ans:Rs 500

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