Question

5. The average height in a class of 25 students is 140 cm. Five more students join the
class and the average height increase to 145 cm. The average height of new
entrants is:
(a) 135 cm
(b) 150 cm
(c) 165 cm
(d) 170 cm​

Answer 1

Step-by-step explanation:

The Average height of students before

140 = x / 25

let x be the summation of their heights

so the summation of their heights are 25 × 140

3500 cm ....1

Five students more join

hence

25 + 5 = 30

so now the new summation of heights will be

30 × 145 = 4350cm...2

..

Now subtracting 1 from 2

4350 - 3500 = 850 cm

so , The average height of new

entrants is:.

850 / 5 = 170 cm (d)

Hope it helps

Answer 2

Answer:

146cm

Step-by-step explanation:

The average height of 25 students is 140cm

total height of 25stdnts

=25*140cm

=3500cm

add 5studnts avg height incrs 1cm...so

30stdnts averge height is 141cm

total height of 30stdnts

=30*141cm

=4230cm

total height of 5stdnts=30stdnts total height-25stdnts total height

=4230- 3500

=730cm

avg height of 5 stdnts

=730/5

=146cm