This chapter covers vital Miscellaneous Quantitative Aptitude Problems frequently seen in competitive and entrance exams, along with quick tricks for solving them. These tricks will help you tackle these problems with ease and ace the quantitative aptitude section of any exam.
Multiple Choice Questions
Que 1: The heights of candles A and B made of the same material but of different thicknesses are in the 3: 2 and their burning times are 4 and 5 hours respectively. If both the candles are lit together, after how much time will the ratio of their respective heights become 3: 4?
(a) 3 hr 10 min
(b) 3 hr 20 min
(c) 3 hr 30 min
(d) 3 hr 40 min
Solution: LCM of (2, 3, 4, 5)=60
Let the heights of the candles be 60 cm and 40 cm (Quantitative Aptitude Problems)
Speed of consumption are 60/4=15 cm/hr and 40/5=8 cm/h
After t time: (Quantitative Aptitude Problems)
\frac{60-15t}{40-8t}=\frac{3}{4}.
t= 10/3 hr= 3 hr 20 min
Option (b) is correct.
Que 2: Garment manufacturer Alfred has received an order for 480 denim shirts. He appointed a team of tailors to fulfill the order. As some of the tailors did not turn up, each of the remaining tailors had to stitch 32 additional shirts. How many tailors had not reported for work?
(a) 6
(b) 4
(c) 2
(d) Data insufficient
Solution: Let the number of appointed tailors= x
Number of absent tailors= t
32 shirts⇒ (x-t) tailors
\frac{32\times (x-t)}{t}.x=480.
From options Put t=4
(x-4).x= 60
x=10 (Quantitative Aptitude Problems)
Option (b) is correct.
Que 3: A teacher instructed her third-grade students to multiply two numbers of different digits, but one of the students accidentally reversed the digits of both numbers. Amazingly, the product obtained by the student was very similar to the product expected by the teacher. How many pairs of such numbers are possible if one of them is less than 20?
(a) 8
(b) 11
(c) 15
(d) 14
Solution: Let, the numbers are 10x+y and 10a+b
(10x+y)×(10a+b)=(10y+x)×(10b+a)
100ax+10ay+10bx+by= 100by+10bx+10ay+ax
99ax= 99by
ax=by
x/y=b/a
The first number (<20)⇒ 12, 13, 14, 15, 16, 17, 18, 19
12⇒ 21, 42, 63, 84
13⇒ 31, 62, 93
14⇒ 41, 82
15⇒ 51
16⇒ 61
17⇒ 71
18⇒ 81
19⇒ 91
Total Pairs= 14
Option (d) is correct.
