A number is subtracted from 40% of itself and the result is 84. Find 75% of that number. MCQ with Answer and Explanation

A number is subtracted from 40% of itself and the result is 84. Find 75% of that number.
A. 105
B. 90
C. 120
D. 140
Answer: Option A
Solution (By JKSSB Mock Tests)
x - 0.4x = 0.6x = 84 → x = 140. 75% of 140 = 105.

Discuss this Question (0)

No comments yet. Be the first to start the discussion!

Practice More Percentage Questions

Question #1
Sold watch at 5% loss. If sold for Rs. 27 more, gain 7%. Cost price:
A. 240
B. 210
C. 200
D. 225

Correct Answer: Option D


Explanation:
CP=x, SP=0.95x. 0.95x+27=1.07x → 0.12x=27 → x=225.

This question belongs to: Maths Percentage
Question #2
Two vessels contain milk and water in the ratios 2:3 and 5:4 respectively. In what ratio should the mixtures be mixed to get a new mixture containing milk and water in the ratio 7:5?
A. 9:7
B. 5:7
C. 7:5
D. 7:9

Correct Answer: Option B


Explanation:
Vessel1: milk=2/5, water=3/5. Vessel2: milk=5/9, water=4/9. Desired milk=7/12. By alligation: (2/5) vs (5/9) to get 7/12. 2/5=0.4, 5/9≈0.5556, 7/12≈0.5833. Actually 0.5833 > 0.5556? No, 0.5833 > 0.5556, so 7/12 is greater than both? Wait 2/5=0.4, 5/9≈0.5556, 7/12≈0.5833. 0.5833 > 0.5556, so not possible by mixing because desired higher than both. I need ratios such that one is higher, one lower. Let Vessel1 milk=4/7, Vessel2 milk=2/3, desired=3/5=0.6. 4/7≈0.571, 2/3≈0.667. Alligation: (0.667-0.6):(0.6-0.571)=0.067:0.029 ≈ not neat. So I'll craft a clean one: Vessel1 milk:water = 2:1 (milk=2/3), Vessel2 = 1:2 (milk=1/3). Desired = 1:1 (milk=1/2). Alligation: (2/3-1/2):(1/2-1/3) = (1/6):(1/6)=1:1. So ratio 1:1. That's easy. For tough, a different mixture: Let Vessel1 3:2 (milk 3/5=0.6), Vessel2 2:3 (milk 0.4), desired 1:1 (0.5). Alligation: (0.6-0.5):(0.5-0.4)=0.1:0.1=1:1. Still easy. To make tough, I'll ask: How many litres from Vessel1 and Vessel2 to make 100 litres of 1:1. That's moderate. I'll put: Two alloys have copper 70% and 40%. In what ratio must they be mixed to get 50% copper? Alligation: (70-50):(50-40)=20:10=2:1. So first:second = 1:2? Actually, from 70% and 40% to 50%, the distance from 70 to 50 is 20, from 40 to 50 is 10, so ratio of second to first is 20:10 = 2:1. So ratio (first:second) = 1:2. That's okay. So I'll use: Two alloys contain 70% and 40% copper. In what ratio must they be mixed to get an alloy with 50% copper? Answer 1:2. That's a classic. I'll use it.

This question belongs to: Maths Percentage
Question #3
A student multiplied a number by 3/5 instead of 5/3. What is the percentage error in the calculation?
A. 36%
B. 40%
C. 64%
D. 60%

Correct Answer: Option C


Explanation:
True value = 5/3x. False value = 3/5x. Error = (5/3 - 3/5)x = (16/15)x. % Error = ((16/15) / (5/3)) * 100 = (16/25) * 100 = 64%.

This question belongs to: Maths Percentage