Search Previous Year Questions

Given 

A can do a work = 30 days 

B can do a work = 40 days 

C can do a work = 48 days 

Formula Used 

Work = time × efficiency 

Calculation 

LCM of (30, 40 and 48) = 240 

let total work be 240 

Efficiency of A = 240/30 = 8/day

Efficiency of B = 240/40 = 6/ day

Efficiency of C = 240/48 = 5/day

1^st 2 days work by A alone , so total work in 2 days = 16 

on 3^rd day, they work together , so total work on 3^rd day = 19 

3 days work = 16 + 19 = 35 

⇒ 3 days × 6 = 35 × 6 

⇒ 18 days work = 210

⇒ another 2 days work = 16 

so, Remaining work by them after 20 days in time = 14/19 = .73 

then total time to complete the work = 20 + .73 = 20.73 days 

∴ The Required answer is 20.73 days.

Given 

X investment for 2 years is Rs. 10,000 

Formula Used 

Compound interest = {P(1 + r/200)2t} – P 

Calculation 

Compound interest = {10,000(1 + 20/200)4} – 10 ,000

⇒ 10,000(1 + 1/10)4 – 10 ,000

⇒ 10,000 × 11/10 × 11/10 × 11/10 × 11/10 – 10 ,000

⇒ 14641 – 10000 = 4641 

∴ The interest will earn after 4 years is Rs 4641.

Given 

Total amount = Rs 1120 

Calculation 

I : II : III = 4/5 ∶ 5/4 ∶ 3/4

I : II : III = 16 : 25 : 15 

Total = 1120 

⇒ 56x = 1120 

⇒ x = 20 

so, 2^nd part = 25x = 25 × 20 = Rs 500 

∴ The required answer is Rs 500

Given 

Total Distance covered in 12 hours = 120 km

Formula Used 

Distance = speed × time 

Calculation 

Let the distance covered on foot be x 

⇒ x/8 + {(120 - x)/11} = 12 

⇒ x = 32 km 

So, time taken to cover 32 km on foot = 32/8 = 4 hours 

∴ The required answer is 4 hours

Given 

A vegetable seller sold vegetable in a week = Rs 1500 

Calculation 

25% on cost price = 1/4 

so , cost price = 4x  and profit = x 

then, selling price = 5x 

⇒ 5x = 1500 

⇒ x = 300 

∴ The profit for vegetable seller is Rs 300

Given

Total marks of exam = 50 

Formula Used 

Percentage = (actual/Total) × 100

Calculation 

Increase in marks = 4 × 2 = 8 

Increase percentage = (8/50) × 100 = 16% 

∴ The percentage of the student is 16% increase

Given 

A and B can do work = 30 days 

Formula used 

Work = Time × Efficiency 

Calculation 

Let the efficiency of A and B be x and y 

⇒ (x + y) × 30 = (x + y) × 24 + x × 8 

⇒ 2x = 6y 

⇒ x : y = 3 : 1 

⇒ Total work = 4 × 30 = 120 

⇒ A can do finish work alone = 120/3 = 40 days 

∴ A can do work alone in 40 days

Given 

Base increased = 30% 

Formula Used 

Successive percentage = x% - y% - (xy/100)% (if one thing is negative)

Calculation 

Increase percentage in Area = 30 - 20 - (30 × 20)/100

⇒ 4% 

∴ The area of triangle is increased by 4%

Formula Used 

Percentage = (actual/total) × 100 

Calculation 

Let the 3^rd number be 100x 

So, 1^st number = 100x + 60% of 100x = 160x 

and 2^nd number = 100x - 20% of 100x = 80x 

Ratio of their numbers = 160x : 80x = 2 : 1 

∴ The ratio of 2 numbers is 2 : 1

Given 

Amounts in simple interest after 10 years = 300% of principal 

So

simple interest after 10 years = 300% of principal - 100% of principal = 200% of principal

Formula Used 

simple interest = principal × rate × time/100

Compound Interest = p(1 + r/100)^t - p 

Calculation 

Let the principal be x 

Simple interest = x × 10 × R/100

⇒ 2x = x × R/10 

⇒ R = 20% 

Compound interest = 50,000(1 + 20/100)² - 50,000 

⇒ 50000 × 36 × 25 - 50000 = 22000 

∴ The compound interest is Rs 22000.