Mathematics MCQs

A man sells Rs.5000, 12 % stock at 156 and uinvests the proceeds parity in 8 % stock at 90 and 9 % stock at 108. He hereby increases his income by Rs. 70. How much of the proceeds were invested in each stock?

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A. 3600(8%), 4200(9%)
B. 4000(8%), 4200(9%)
C. 3600(8%), 4000(9%)
D. 4000(8%), 4000(9%)
✅ The correct answer is option A. 3600(8%), 4200(9%).
S.P of Rs. 5000 stock = Rs. [(156/100)*5000] = Rs. 7800.

Income from this stock = Rs. [(12/100)*5000] = Rs. 600.

A is thrice as good a work man as B and takes 10 days less to do a piece of work than B takes. B can do the work in:___________?

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A. 15 days
B. 14 days
C. 16 days
D. 30 days
✅ The correct answer is option A. 15 days.
Raio of times taken by A and B = 1 : 3

If the difference of time is 2 days, B takes 3 days. If the difference of time is 10 days.

B takes [3/2×10]=15 days

A and B can complete a work in 15 days and 10 days respectively. They started doing the work together but after 2 days B had to leave and A alone completed the remaining work. The whole work was completed in___________?

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A. 8 days
B. 10 days
C. 12 days
D. 15 days
✅ The correct answer is option C. 12 days.
(A.+ B)’s 1 day’s work = ( 1/15 + 1/10 ) = 1/6 Work done by A and B in 2 days = ( 1/6 X 2 ) = 1/3 Remaining work = ( 1 – 1/6 ) = 2/3

Now, 1/15 work is done by A in 1 day. so 2/3 work will be done by A in ( 15 X 2/3 ) = 10 days Hence, total time taken = (10 + 2) = 12 days.