Numerical Ability

(Five prime numbers greater than 30 are-31, 37, 41, 43 & 47Average = 1/5 (31 + 37 + 41 + 43 + 47) = 1/5 X 199 = 39.8)

(Average of the remaining 48 numbers = 50 X 38 - 45 - 5548 = (1900 - 100) ÷ 48 = 1800/48 = 37.5)

(C. P. of one mango = Rs. 1/15S. P. of one mango = 125% of C. P. of one mango = 125% X 1/15 of a rupee= 1/12 of a rupee. Therefore, 12 for a rupee)

(90% of cost price = 225 then;110% of cost price = 225/90 X 110 = Rs.275.)

(Alcohol is 20% of 5 litres, i. e. one litre. When 1 litre water is added, mixture becomes 6 litres, in which alcohol is 1 litre. Therefore, strength of alcohol = 1/6 X 100% = 50/3%)

(If marked price is Rs.100, then cost price is Rs.80 & selling price is Rs.85 Therefore, gain percent = 5/80 X 100% = 6.25%)

(Using the short-cut: Gain% = 2x + x% of x = 2 X 10 + 10% of 10 = 20 + 1 = 21% OR If he starts with Rs.100, he gets goods worth Rs.110. By selling goods worth Rs.110, he getsRs.110 X 110% = Rs.121. Therefore his gain is 21%)

(Cost of one toffee of first kind = 24/5 p Cost of one toffee of second kind = 42/6 = 7p Cost of one toffee of mixture = 72/12 = 6p By method of Alligation1st kind 2nd kind 24/5 76(7 - 6) (6 - 24/5) Ratio = (7 - 6): (6 - 24/5) = 1:6/5 = 5:6. Therefore, number of toffees of first kind = 5/6 X 300 = 250)

(Since the total part of milk & water in each is same, we add the part of milk & water separately. Required ratio is = (2 + 4 + 3) : (3 + 1 + 2) = 9 : 6 = 3:2)

(If x be the number of junior teachers, then, 5 X 3700 + x X 2300 = (5 + x) X 3000= 18500 + 2300x = 15000 + 3000x = 700x = 3500 or x = 5)

(The compound interest for the forth year = Rs. 680 + 10% of Rs. 680 = Rs. (680 + 68) = Rs. 748)

(We want to know that if the sum of money, say, Rs.100 becomes Rs.200 in 7.5 years, then in how many years it will become Rs.400. The simple interest earned is Rs.300 & this will amount to in 3 X 7.5 years, i. e. 22.5 years)

(If the principal be Rs.100, S. I. is Rs.60 & rate is 10%Therefore, time = I X 100 = 60 X 100 = 6 years) P X R 100 X 10

(Whatever be the sum, it doubles in 7 years; in another 7 years, it will become 4 times & again in 7 years it becomes 8 times. Hence in 21 years, the sum will be 8 times.)

(S.I. for two years = Rs. 10,000 X 2 X 10 = Rs. 2000  100 Interest for first year = Rs. 10000 X 1 X 10 = Rs.1000   100 Interest for second year = Rs. 1000 + 10% of Rs. 1000 = Rs. 1100 Total interest for 2 years (C.I.) = Rs. 2100 Difference = Rs. 100)

(No interest is earned on Rs. 840 since it is the simple interest, i. e. simple interest remains the same. Hence no change.)

(Part of the cistern filled in one minute == 1/10 - 1/12 = 6 - 5/60 = 1/60 Therefore, the cistern is full in 60 minutes or in an hour)

(Work done by both in one day = 1 ÷ 7.5 = 2/15 Work done by Salim in one day = 1/20. Therefore, work done by Akram in one day = 2/15 - 1/20 = 8 - 3/60 = 5/60 = 1/12. Hence Akram alone can do the work in 12 days.)

(2 men + 3 boys can do a job in 5 days, so in one day-5 X (2 men + 3 boys) can do it in one day. Similarly, 4 X (3 men + 2 boys) can do it in one day. Therefore, 5 X (2 men + 3 boys) = 4 X (3 men + 2 boys)2 men = 7 boys. Hence, work ratio = 7 : 2)

(Distance travelled in 20 seconds = (20 X 5/18 X 90) m = 500mTherefore, length of platform = (500 - 120) m = 380 m)

(If x km be the distance required, then, x/10 - x/12 = 8/60 Hence, x = 8 km)

(Two trains are meeting after 4 hours. The relative speed of two trains is (70 + 90) km i. e. 160 kmph. Therefore, Distance = (4 X 160) km = 640 km.)

(√100/? = 4/40 = 10/? = 1/10. Therefore, ? = 10 X 10 = 100)

(752 + 3147 + 1008 + 29 = 4936)

(192/100 X 12.5 = 24 which is 50% of 48)