Problem-solving Questions and Answers
Practice ModeShowing 10 of 50 questions
Q21
If 4 men or 6 boys can do a work in 12 days, how many days will 3 men and 4 boys take?
Answer: Option B
Explanation: 1 man = 1.5 boys, 3 men + 4 boys = 4.5 + 4 = 8.5 boys, Days = (6 × 12)/8.5 ≈ 9 days
Q22
A sum of money triples itself in 8 years at simple interest. Rate = ?
Answer: Option C
Explanation: SI = 2P, 2P = (P × R × 8)/100 → 2 = 8R/100 → R = 25%
Q23
The ratio of present ages of A and B is 3:4. After 5 years, sum of their ages = 45. Find A's age.
Answer: Option A
Explanation: Let ages be 3x and 4x, After 5 years: (3x+5)+(4x+5)=45 → 7x+10=45 → 7x=35 → x=5, A's age = 3×5=15
Q24
If a man walks 20 km in 4 hours, how much will he walk in 6 hours?
Answer: Option B
Explanation: Speed = 20/4 = 5 km/h, Distance in 6 hours = 5 × 6 = 30 km
Q25
A and B can do a work in 10 and 15 days respectively. A alone works 2 days, B alone 3 days. Remaining work = ?
Answer: Option B
Explanation: A's work = 2/10 = 1/5, B's work = 3/15 = 1/5, Total done = 2/5, Left = 1 - 2/5 = 3/5
Q26
A man borrows ₹6000 at 6% simple interest per annum. Find SI for 4 years.
Answer: Option A
Explanation: SI = (6000 × 6 × 4)/100 = ₹1440
Q27
A can do a work in 10 days, B in 20 days. A and B work together for 4 days. Fraction left = ?
Answer: Option C
Explanation: Combined 1 day work = 1/10 + 1/20 = 3/20, Work in 4 days = 12/20 = 3/5, Left = 1 - 3/5 = 2/5
Q28
A sum of money at 5% per annum SI becomes ₹3150 in 3 years. Find principal.
Answer: Option A
Explanation: SI for 3 years = 15% of P, Amount = 115% of P = 3150, P = 3150/1.15 ≈ ₹3000
Q29
A can do a work in 8 days, B in 12 days. How many days will they take working together?
Answer: Option A
Explanation: Combined 1 day work = 1/8 + 1/12 = 5/24, Days = 24/5 = 4.8 days
Q30
A man sells an article at 20% loss for ₹400. CP = ?
Answer: Option A
Explanation: CP × (1 - 20/100) = 400 → CP × 0.8 = 400 → CP = 400/0.8 = ₹500