Arithmetic Mcqs

The average of 11 numbers is 10.9. If the average of first six is 10.5 and that of the last six is 11.4 the sixth number is_____________?

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The average of 11 numbers is 10.9. If the average of first six is 10.5 and that of the last six is 11.4 the sixth number is_____________?A. 11.0
B. 11.3
C. 11.4
D. 11.5

Sum of 11 numbers = 11×10.9 = 119.9
Sum of 1st 6 numbers = 6×10.5 = 63
So, sum of last 5 numbers = 119.9-63 = 56.9
And sum of last 6 numbers = 6×11.4 = 68.4
Hence sixth number will be = 68.4-56.9= 11.5

 

Two automobiles are 150 kilometers apart and traveling toward each other. One automobile is moving at 60km/h and the other is moving at 40km/h mph. In how many hours will they meet?

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Two automobiles are 150 kilometers apart and traveling toward each other. One automobile is moving at 60km/h and the other is moving at 40km/h mph. In how many hours will they meet?

A. 2.5
B. 2.0
C. 1.75
D. 1.5
E. 1.25

One moves at 60km/h, so in an hour, he’ll travel 60km
The other moves at 40km/h, so in an hour, he’ll travel 40km
This is towards each other, so, in an hour, we can say that they’ll get 60+40=100km closer.
This means that they get closer at 100km/h
Given that we have the distance of 150km, and the speed of closure at 100kmh, we can now use the equation
S=D/T
Rearrange to find T (times both sides by T)
S x T = D (now divide both sides by S)
T=D/S
Time = 150km divided by 100km/h
Time = 1.5 hours
Or one hour and 30 minutes

If the average marks of three batches of 55, 60 and 45 students respectively is 50, 55, 60, then the average marks of all the students is:

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If the average marks of three batches of 55, 60 and 45 students respectively is 50, 55, 60, then the average marks of all the students is:

A. 53.33
B. 54.68
C. 55
D. None of these
55 students get average marks of 55%.
so 55*50=2750
similarly 60*55=3300
& 60*45=2700
now total no of marks obtain by all students of three batches= 2750+3300+2700=8750/=
Total no of students= 55+60+45=160.
By dividing total marks on each student , we get average marks obtain by each student
so 8750/160 = 54.68
Solution Added by: MUHAMMAD SHOAIB

If a car is sold for Rs..50000 the profit is 17 percent, what would be profit percentage if sold for Rs. 47000?

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If a car is sold for Rs..50000 the profit is 17 percent, what would be profit percentage if sold for Rs. 47000?

A. 14.85%
B. 9.98%
C. 16.20%
D. 14.50%
Solution by Ahmad hassan :
Actually, the question is this.
If a person sells his car in 50000 rupees and got 17% profit. What will be the profit in percentage if he sold this car in 47000 rupees?
Solution
Profit = 17 %
Sp of car = Rs 50000
Cp = sp/1 + .profit percentage
Cp = 50000/1+.17
Cp= 50000/1.17= Rs 42735.04
Now he wants to sell at Rs 47000
New sp = Rs 47000
Profit sp-cp = 47000-42735.04 = Rs 4264.96
Profit % = profitx100/cp
Profit % = 4264.96×100/42735.04 = 9.98 %
New profit % = 9.98
___________________________________________
Solution by Vicky :
total sold price with 17% profit =50,000 (Including 17% profit)
now lets break this 50,000
50,000=X(original cost of car)+0.17x(17% profit) :- x is supposed cars original price
50,000=x+0.17x
x=50,000/1.17 (By taking x common)
x=42,735 (which is Original cost of car)
now again his is selling his damn car at Rs 47,000, that means his profit this time will be
47,000-42,735(original amount of car we just calculated above)=4265 (profit this time)
now calculate the percentage of this above calculated Profit with simple formula
4265/42735*100= 9.98% (Answer) cheers