71. How many terms are there in 20, 25, 30……… 140.
(A) 22
(B) 25
(C) 23
(D) 24
Answer:
(B) 25
Explanation:
This is an arithmetic progression where a = 20, d = 5, and l = 140. n = ((l – a) / d) + 1 = ((140 – 20) / 5) + 1 = (120 / 5) + 1 = 24 + 1 = 25.
72. An error 2% in excess is made while measuring the side of a square. The percentage of error in the calculated area of the square is:
(A) 2%
(B) 2.02%
(C) 4%
(D) 4.04%
Answer:
(D) 4.04%
Explanation:
Let the true side be x. Measured side = 1.02x. True area = x². Calculated area = (1.02x)² = 1.0404x². Percentage error = ((1.0404 – 1) / 1) * 100 = 4.04%.
73. Ram sells a commodity to Rahim at a profit of 10%. Rahim sells the commodity back to Ram at a loss of 10%. In this transaction:
(A) Ram neither losses nor gains
(B) Ram makes a profit of 11%
(C) Ram makes a profit of 20%
(D) Rahim loses 20%
Answer:
(B) Ram makes a profit of 11%
Explanation:
Let CP for Ram be 100. He sells to Rahim for 110 (makes +10 profit). Rahim sells back at 10% loss on 110, which is 99. Ram buys it for 99, saving 1. Total profit for Ram = 10 (first sale) + 1 (saved on buyback) = 11%.
74. If a^x = b^y, then:
(A) log a/b = x/y
(B) log b/a = y/x
(C) log a/log b = x/y
(D) log a/log b = y/x
Answer:
(D) log a/log b = y/x
Explanation:
Taking logs on both sides: x * log a = y * log b. Rearranging this gives log a / log b = y / x.
75. The ratio of two numbers is 3:4 and their HCF is 4. What is LCM of these two numbers?
(A) 12
(B) 24
(C) 36
(D) 48
Answer:
(D) 48
Explanation:
If the ratio is 3:4 and the HCF is 4, the numbers are 3 * 4 = 12 and 4*4 = 16. The LCM of 12 and 16 is 48.
