# Mixed Quantitative Aptitude Questions Set 210

1. If sum of upstream and between downstream speed of a boat is 80 kmph , and the boat travels 90 km . upstream in 3hr Find the time taken by boat to cover 120 km downstream
121/5 hr
13/5 hr
12/5 hr
12/7 hr
12/11 hr
Option C
let b= speed of the boat
w= speed of water
u= upstream speed= b-w
d= downstream speed = b+w
So u +d= 80
that is b-w+b+w= 80
=>b= 40
40-w= 90/3 = 30
w= 10 kmph
b+w= 120/t
t= 120/50 = 12/5 hr

2. The difference between simple interest and compound interest of a certain sum of money at 10 % per annum for 2 years is Rs. 40. Then the sum is ;
Rs.5000
Rs.4000
Rs.6000
Rs.7000
Rs.8000
Option B
CI- SI = P ( r/100 ) ^2
40 = p( 10/100) ^2
=> P= Rs.4000

3. Compound interest of a sum of money for 2 years at 4 percent per annum is Rs . 2500 Simple interest of the same sum of money at the same rate of interest for 2 years will be :
Rs.2350
Rs.2456
Rs.2459
Rs.2450
Rs.2451
Option E
CI= P( 1+r/100 ) ^t – P
2500 = P (( 1-4/100)^2 -1)
=> p= 2500 * 625 / 51=Rs. 30637.25
SI= 30,637.25 * 4* 2/100=Rs.2451

4. The are two positive integers a and b . What is the probability that a + b is odd ?
1/2
1/3
1/4
1/5
1/6
Option A
Sum of positive integers is either odd or even.
So the probality = 1/2

5. Kailash sells apples at a loss of 44 % but he uses a false scale which is 30 % less than its true weight . Find the loss / gain percent ?
21%
22%
20%
23%
24%
Option C
Let CP = Rs.100 for 100g
So SP=Rs. 56 for 70g
and SP =Rs. 80 for 100g
loss%=100-80/100 * 100 = 20%

6. Average age of A ,B and C is 80 years . When D joins them the average age becomes 70 years . A new persons E, whose age is 4 years more than D replaces A and the average of B , C, D and E becomes 75 years . What is the age of A ?
20 yrs
21 yrs
22 yrs
23 yrs
24 yrs
Option E
A+B+C = 3* 80 = 240 yrs
A+B+C+D= 4* 70 = 280 yrs
D age= 280-240 = 40yrs
=> E age= 40 + 4 = 44 yrs
B+C+D+E age = 75* 4= 300 yrs
B+C age = 300 – 40-44=216
A age = 240-216=24 yrs

7. The population of sparrows in a particular locality is decreases by certain rate . If the current population of sparrows be 36450 and the ratio of decrease in population for second year and 3rd year be 10 : 9 . What was the population of sparrows 3 years ago ?
50,000
55000
53,000
52,000
51,000
Option A
Ratio = 10:9
=> 10-9 /10 * 100 = 10%
So p ( 1-10/100 ) ^3 = 36450
p= 50,000

8. Tap A can fill a water tank in 25 minutes , tap B can fill the same tank in 40 minutes and tap C can empty the tank in 30 minutes . If all the three taps are opened together , In how many minutes will the tank be completely filled up or emptied ?
31 3/10 minutes
26 7/12 minutes
34 11/19 minutes
24 1/5 minutes
31 11/19 minutes
Option E
A–> 25
B—>40
C—> -30
Required answer = (25 x 40 x 30) / (40 x 30 + 25 x 30 – 25 x 40)
== 600 / 19 = 31 11/19 minutes

9. A dog starts to chase a man . When the man goes 20 steps the dog moves 16 steps and 10 steps of the dog are equal to 14 steps of the man . The ratio of the speeds of the dog and the man is :
28 : 25
28 : 25
28 : 25
28 : 25
28 : 25
Option D
dog : man
Steps –> 16 : 20
distance–> 14 : 10
=224 : 300
speed= 28 : 25

10. A train runs with a speed of 400 km/hour. What will be its speed in m/sec?
112.11 m/sec
111.11 m/sec
113.11 m/sec
115.11 m/sec
117.11 m/sec
Option B
Speed in km/ hour =400

Speed in m/sec = 400 x 5/18 = 500/9 m/sec = 111.11 m/sec