NTSE Stage 2 SAT 2015 Question Paper

When a natural number x is divided by ‘5’, the remainder is 2
∴ x=5P+2 ... (i)
When a natural number y is divided by ‘5’ the remainder is 4
∴ ;y=5Q+4 ... (ii)
When x + y is divided by ‘5’, the remainder is z
Adding Eq. (i) and (ii), we get
x+y=5(P+Q)+6
Now when x + y is divided by ‘5’ remainder will be 1
∴ z=1
Hence the value of

2z−5

3

=

2(1)−5

3

=−1