Reduction in consumption = (20/120) x 100% = 50/3%

Correct Option: C

Reduction in consumption = (20/120) x 100% = 50/3%
∴ Reduction in consumption /Original consumption = (50/3) / 100 = 1/6 = 1 : 6

∵ (62% of N - 38% of N) =144
⇒ 24% of N = 144

Correct Option: A

∵ (62% of N - 38% of N) =144
⇒ 24% of N = 144
∴ N = (144 x 100)/24 = 600

Let third number be N
Then, first number = 70% of N = 7N/10 and,
Second number = 63% of N = 63N/100
Difference = 7N/10 - 63N/100 = 7N/100

Correct Option: D

Let third number be N
Then, first number = 70% of N = 7N/10 and,
Second number = 63% of N = 63N/100
Difference = 7N/10 - 63N/100 = 7N/100
∴ Required percentage = (7N/100) x (10/7N) x 100 % = 10%

∵ 72¹/₂% of N = 87
⇒ {(145/2) x N} / 100 = 87

Correct Option: C

∵ 72¹/₂% of N = 87
⇒ {(145/2) x N} / 100 = 87
∴ N = (87 x 2 x 100) / 145 = 120

∵ 137¹/₂% of N = 33
⇒ {(275/2) x N} / 100 = 33

Correct Option: B

∵ 137¹/₂% of N = 33
⇒ {(275/2) x N} / 100 = 33
∴ N = (33 x 2 x 100) / 275 = 24