21. A boat moves down stream at the rate of 1 km in 6 minutes and upstream at the rate of 1 km in 10 minutes. The speed of current is?
Answer:
Explanation:If speed(in kmph) of the boat=b and current=c, then
In downstream time taken(in hrs.)=1/(b+c)=6/60=1/10 or b+c=10 ---(i) &
In upstream time taken(in hrs.)=1/(b-c)=10/60=1/6 or b-c=6 ---(ii)
From (i) & (ii), b=8, c=2
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22. Three men invested sum and their ratio is 5:7:6. Profit is 5400. Then what is B's share?
Answer:
Explanation:B's share =7/18*5400=2100
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Wipro NLTH
23. The population of a town is 18000. It increases by 10% during first year and by 20% during the second year. The population after 2 years will be :
Answer:
Explanation:10% of 18000 is 1800
After first year the population is 18000+1800
The total population becomes 19800
In second year the population becomes 20% of first year
So 20% of 19800 is 3960
19800+ 3960 gives 23760
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24. Population of a colony of ants is increasing by 20% per day. If the population on Monday was 3000, on which day of that week the population would be 5184 ?
Answer:
Explanation:On monday the population is 3000, and 20% of 3000 is 600
On tuesday the population is 3600(3000+600) and 20% of 3600 is 720
On wednesday the population is 4320(3600+720) and 20% of 4320 is 864
On thursday the population is 5184(4320+864).
So the answer is Thursday.
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Wipro NLTH
25. The largest measuring cylinder that can accurately fill 3 tanks of capacity 98,182 and 266 litres each, is of capacity:
Answer:
Explanation:98,182,266 all are divisible by 14
So ans 14 litres (you take HCF also)
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Wipro NLTH
26. What is John's age?
(I) In 15 years John will be twice as old as Dias would be
(II) Dias was born 5 years ago
The correct answer is:
Answer:
Explanation:option c is correct because according to given information we
can't find john's age with out the age of dias.
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Wipro NLTH
27. The percentage discount offered for"Buy 6 get 1 free is"?
Answer:
Explanation:cost of 6 items=rs6
cost of 7 items=rs7
we get 7 items for 6rs
so discount =7-6/6*100 apox 14.29 %
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Wipro NLTH
28. Initially a number was 150. It was reduced by 20%. How much it is to be reduced to become 108?
Answer:
Explanation:Let x=150
Reduced by 20%
20% of 150=30
150-30=120
To make 120 as 108 subtract 12 i.e.10% of 120
120-10% of 120=108
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Wipro NLTH
29. A sum of Rs. 427 is to be divided among A, B and C in such a way that 3 times A's share, 4 times B's share and 7 times C's share are all equal. The share of C is?
Answer:
Explanation:A+B+C=427
3A=4B=7C=k(say)
A=k/3, B=k/4, C=k/7
k/3+k/4+k/7= 427
28k + 21k + 12k = 427*84
61k = 427*84
k=7*84
C=k/7
C=84
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Wipro NLTH
30. The average age of 40 students of a class is 15 years. When 10 new students are admitted, the average is increased by 0.2 years. The average age of new students is :
Answer:
Explanation:Total Student -year for 40 students =40*15=600.
when 10 new students were admitted the avg. increased by 0 .2 or becomes 15.2 years.
Therefor new Student-year for 50 students=15.2*50=760.
Student-year for 40 students 600 & for 50 students its 760, difference = 160.
hence we can say that 160 student-years were added, which is of 10 student.
Hence the average for 10 new students = 160/10 or 16 years
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Wipro NLTH
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