Question

A tanker contains 500 litres of water. Due to a small hole in the tanker, the quantity of water is decreasing at the rate of 9 litres every hour. What will be the quantity of water in the tank after 10 hours ?
(1) 410 litres
(2) 491 litres
(3) 400 litres
(4) 390 litres

Answer 1

quantity of water decrease in 10 h.=9*10=90
500-90=410l.

Answer 2

Answer:

option (1) is correct

Step-by-step explanation:

concept:

The n th term of A.P

a, a+d, a+2d........ is a+(n-1)d

Initially the tanker contains 500 litres.

The quantitiy of water after1 hour is 491

The quantitiy of water after2 hours is 482

and so on

Here,

500, 491, 482.......... forms an A.P with common difference- 9

This implies

the quantity of water after n hours

=( n+1)th term of the A.P

= a+(n+1-1)d

= a+nd

The quantity of water after 10 hours is

a + 10d

=500 + 10(-9)

=500 - 90

= 410 litres.