Question

the petrol price were hiked by 3% and than they were rolled back by 2% find the net increase and decrease per cent in the price

Answer 1

by using formula net effect = x + y + (xy/100)
put x=3, y= -2
3-2-(6/100) = 1-0.06= 0.94% increase.

Answer 2

Answer:

Given, u=20m/s

t

1

=5s

t

2

=8s

Graph: (Refer to Image)

(1) Distance travelled in first 5 sec= area of ABDE= 20×s=80m

(2) Distance travelled after the brakes are applied (area of BCD)=

2

1

×8×5=20m

(3) Total distance travelled= AreaofABCDE+AreaofBCD=80+20=100m

(4) Acceleration during the first 5 sec= 0, because uniform velocity.

(5) Acceleration during the last 8 sec= v=0,u=20m/s,t=8sec

⇒v=u+at⇒0=20+a(8)

⇒a=−2.5m/s

2

(slope of the line DC