Question

Question number 24





Below question

Answer 1

Given Ap= 20 ,18,16

D=a2-a1

D=-2

a10th=20+9*-2

=2

So in the 10th min he cover 2m

The total distance cover in 10 min=

S10=10/2(40+9*-2)

So s10=110m

So he will cover 110m in 10 min

Answer 2

This question is of AP
Here is you solution..
let,
t1 =a= 20
t2 = 18
t3 = 16
so d i .e. distance be
t2 - t1 = 18 - 20 = -2
Here we have to find t10 and s10
So according to formula
tn = a + (n-1) d
t10 = 20 + (10-1) -2
= 20 + (-18)
= 20 - 18
= 2
so the distance covered by her on 10 th minute will be 2 m
Sn = n/2 (2a + (n-1) d)
S10 = 10/2 ( 2 ×20 + 10-1 × -2)
= 5 (40-18)
= 5 ( 22)
= 110
Therefore she will cover 110 m in 10 mins