Quantitative Aptitude - Arithmetic Ability Questions

There should be 90 instead of 80
so we can have a series
5, 5x3, 15x2, 30x3, 90x2, 180x3, 540x2 and 1080x3 and so on...

Area to be plastered = 2l+b×h+l×b 

=225+12×6+25×12=744sq.m 

Cost of plastering = 744×75100=Rs.558                       

As per the BODMAS rule, the priority in which the operations should be done is:

Note: Addition and subtraction can be treated on same priority (from left to right) when they are in consecutive order. ? = 1234 + 2345 – 3456 + 4567 ? = 3579 - 3456 + 4567 ? = 123 + 4567 ? = 4690

Let the required numbers be 33a and 33b. 

Then 33a +33b= 528   =>   a+b = 16.

Now, co-primes with sum 16 are (1,15) , (3,13) , (5,11) and (7,9).

Therefore, Required numbers are  ( 33 x 1, 33 x 15), (33 x 3, 33 x 13), (33 x 5, 33 x 11), (33 x 7, 33 x 9)

The number of such pairs is 4