Quantitative Aptitude - Arithmetic Ability Questions

If earlier he is getting Rs. 1  per hr and working for 1 hr, income = Rs. 1
Now he is getting Rs 1.3333 per hr and working for 0.66667 hrs

Then income for 0.66667 hrs = Rs. 0.8889.

If payment per hr is increased by 33.33 %  and working hours dereased by 33.33%, then 11.11 % decrease in income.

Money lent to A+B = (300 + 540) = Rs. 840 

Amount received = Rs. 1032 

Interest received = Rs. 1032 - Rs.840 = Rs. 192

Interest on Rs. 300 lent to A for 1 year = 300×1×4100 = Rs. 12 

Interest on Rs.540 lent to B for 1 year = 540×6×1100 = Rs. 36 

Total yearly interest = Rs.(12+36) = Rs.48 

If interest is Rs. 48, time = 1 year 

If interest is Rs. 192, time =  192/48 = 4 years 

Let the numbers be a and b . Then, a+b =55 and ab = 5 x 120 = 600.

Therefore, Required sum = 1a+1b=a+bab=55600=11120

Required number of signals = 5P1 + 5P2 + 5P3 + 5P4 + 5P5

= 5 + 20 + 60 + 120 + 120 = 325

 Since 8 does not occur in 1000, we have to count the number of times 8 occurs when we list the integers from 1 to 999. Any number between 1 and 999 is of the form xyz, where 0≤x,y,z≤9.

Let us first count the numbers in which 8 occurs exactly once.

Since 8 can occur atone place in 3C1ways. There are 3 x 9 x 9 such numbers.

Next, 8 can occur in exactly two places in 3C2×9 such numbers. Lastly, 8 can occur in all three digits in one number only.

Hence, the number of times 8 occur is 

 1×3×92+2×3×9+3×1 = 300

Let no. of boys be 'B' and no. of girls be 'G'

Here from given data,

B + G = 1650 .....(1)

B - G = 400 .....(2)

From (1) & (2), we get

2B = 2050

=> B = 1025

=> G = 1650 - 1025 = 625

Hence, the % of girls = 625 x 100/1650

=> 38% (approx).

S = { HHH, HHT, HTH, HTT, THH, THT, TTH, TTT }

=> n(S) = 8

E = { HHH, HHT, HTH, THH }

=> n(E) = 4

P(E) = 4/8 = 1/2