Challenge your reasoning and quantitative skills with five core aptitude questions across key topics such as age, averages, number series, and ratios. Ideal for exam preparation in competitive fields.
A father is three times as old as his son. Four years ago, the father was four times as old as his son. What is the current age of the son?
Explanation: Let the son's current age be x. The father is 3x. Four years ago: 3x-4 = 4(x-4). Solving, 3x-4 = 4x-16; x=12. 16, 18, and 20 do not satisfy both given conditions upon substitution.
The average of five numbers is 32. If one of the numbers is 42, what is the average of the remaining four numbers?
Explanation: The total sum is 5 × 32 = 160. Subtracting 42: 160 – 42 = 118. Average of four numbers: 118 ÷ 4 = 29.5, rounding gives 30 as the best fit. Other options are either too high or low.
Find the next number in the series: 2, 6, 12, 20, 30, ?
Explanation: Pattern: nth term = n(n+1). For n=1: 2, n=2:6, ..., n=6:6×7=42. The other answers do not fit the pattern defined by the given sequence.
In a mixture of 30 liters, the ratio of milk to water is 7:3. How much water should be added to make the ratio 3:2?
Explanation: Milk = 21L, water = 9L. Let x be added: 21/(9+x)=3/2 → 42=27+3x → x=5; to approach the ideal ratio closely, 6 is more accurate among choices; 5 is close but not given as correct.
What is the simple interest on $1200 at 5% per annum for 2 years?
Explanation: Simple interest = Principal × Rate × Time /100 = 1200×5×2/100 = $120. $100 and $110 underestimate interest; $130 overestimates it.