Quantitative Aptitude Test

Quantitative Aptitude Test Question 1

If x and y are the two digits f the number 653xy such that this number is divisible by 80, then x+y is equal to:
(i) 2
(ii) 3
(iii) 4
(iv) 6
Solution:
Since 653xy is divisible by 2 as well as by 5, so y = 0
Now 653x0 is divisible by 8 so 3x0 is also divisible by 8.
By hit and trial x=6 and x+y = 6
(I am thankful to the contributors below on pointing out mistake in the answer.)

Quantitative Aptitude Test Question 2

The smallest number which when diminished by 3 is divisible by 21,28,36 and 45 is... (i) 869
(ii) 859
(iii) 4320
(iv) 427
Solution:
The required number = l.c.m. of (21,28,36 ,45)+3=1263

Quantitative Aptitude Test Question 3

If 1.5x=0.04y then the value of (y-x)/(y+x) is (i) 730/77
(ii) 73/77
(iii) 7.3/77
(iv) None
Solution: x/y = 0.04/1.5 = 2/75
So (y-x)/(y+x) = (1 - x/y)/(1 + x/y) = (1 - 2/75)/ (1 + 2/75) = 73/77

Quantitative Aptitude Testing Question 4

The average age of a class is 15.8 years. The average age of boys in the class is 16.4 years while that of girls is 15.4 years. What is the ratio of boys to girls in the class?(i) 1:2
(ii) 3:4
(iii) 3:5
(iv) None of these
Solution:
Let the ratio be k:1.
Then k*16.4+1*15.4 + (k+1)*15.8 (16.4-15.8)k = 15.8 - 15.4 k=0.4/0.6 = 2/3 so required ratio = 2:3
Mr. Ankit from India has corrected the answer as:
Then k*16.4+1*15.4 = (k+1)*15.8 (16.4-15.8)k = 15.8 - 15.4 k=0.4/0.6 = 2/3 so required ratio = 2:3
You may respond to him at the post below with his name.

Quantitative Aptitude Testing Question 5

If one-seventh of a number exceeds its eleventh part by 100 then the number is… (i) 770
(ii) 1100
(iii) 1825
(iv) 1925
Solution:
Let the number be x. Then X/7 - x/11 =100 11x-7x = 7700 x=1925.

Quantitative Aptitude Test Question 6

The ratio of Rita's age to her mother's age is 3:8. The difference of their ages is 35 years. The ratio of their ages after 4 years will be:(i) 7:12
(ii) 5:12
(iii) 38:43
(iv) 42:47
Solution:
Let their ages be 3x and 8x
8x - 3x =35
x =7
Their present ages are 21 and 56 years.
Ratio of their ages after 4 years are 25:60 = 5:12

Quantitative Aptitude Test Question 7

Gold is 19 times as heavy as water and copper is 9 times as heavy as water. In what ratio should these be mixed to get an alloy 15 times as heavy as water? (i) 1:1
(ii) 2:3
(iii) 1:2
(iv) 3:2
Solution:
Let 1gm of gold be mixed with x gm of copper to give (1+x)gm of the alloy.
1G=19W, 1C = 9W and alloy = 15W 1gm gold + xgm Copper = (1+x)gm alloy 19W+9Wx = (1+x)*15W x = 4W/6W = 2/3
So ratio of gold and copper is 1:2/3 or 3:2

Quantitative Aptitude Test Question 8

A tap can fill the tank in 15 minutes and another can empty it in 8 minutes. If the tank is already half full and both the taps are opened together, the tank will be: (i) filled in 12 min
(ii) emptied in 12 min
(iii) filled in 8 min
(iv) emptied in 8 min
Solution:
Rate of waste pipe being more the tank will be emptied when both taps are opened.
Net emptying workdone in 1min =(1/8 -1/16)= 1/16
So full tank will be emptied in 16 min
Half tank will be emptied in 8 minutes.

Quantitative Aptitude Test Question 9

A man can row 5 kmph in still water. If the river is running at 1kmph, it takes him 75 minutes to row to a place and back. How far is the place? (i) 3km
(ii) 2.5 km
(iii) 4 km
(iv) 5 km
Solution:
Speed downstream = (5+1)km/hr = 6 km/hr Speed upstream = (5-1)km/hr = 4 km/hr Let the required distance be x km x/6 + x/4 = 75/60 2x+3x = 15 x = 3km

Quantitative Aptitude Test Question 10

729 ml of a mixture contains milk and water in ratio 7:2. How much of the water is to be added to get a new mixture containing half milk and half water? (i) 79 ml
(ii) 81 ml
(iii) 72 ml
(iv) 91 ml
Solution:
Milk = (729 * (7/9))=567ml
Water = (729-567)= 162ml
Let water to be added be x ml 567/(162+x) = 7/3 1701 = 1134 + 7x x = 81ml

Note:

Discussion on Answer to Question No.10 has taken a long time. Different visitors gave different answers. However, majority of the visitors have contributed that the answer should be 405 ml of water as: The quantity of milk in the mixture is
7/(7+2) X 729
= 7/9 X 729
= 567mL
The quantity of water then shall be
729 - 567 = 162mL
If the final mixture would contain half milk and half water, there must be equal quantity of both.
So in order to make up for water, we'll need to add
567mL - 162mL= 405mL of water