Telanagana SCERT Solution Class VIII (8) Math Chapter 10 Direct and Inverse Proportions Exercise 10.3
(1) Price of potatoes = RS 8 per kg.
Let she will buy y2 kg if the price is RS 10 per kgg.
Then, x1 =8, y1 =5, x2 =10, y2 =?
x1/x2 = y2/y1
= 8/10 = x/5
= y2 = 40/10 =4 kg.
(2) For 70 days, the number of people living there =500
Then, x1 =500, y1 =70, x2 =(500+200) =700, y2 =?
x1/x2 = y2/y1
= 500/700 = y2/70
= y2 = 500X700/700 =50 day.
(3) Let the 9 men can do the same work in y2 days
Then, x1 =36, x2 =9, y1 =12, y2 =?
x1/x2 = y2/y1
= 36/9 = y2/12
= y2 = 36X12/9
Therefore, y2 =48 days
(4) Let the 8 pipes takes y2 times
Then, x1 =5, x2 =8, y1 =80, y2 =?
= 5/8 = y2/80
= y2 = 80X5/8 =50 minutes.
(5) We know distance = speed X time
The distance = 16X10 =160 nautical miles.
Again speed = 160/8 =20 mile/hour
So, the increased speed is (20-16) =4 mile/hour.
(7) Let required workers be y2
Then x1 =48, x2 =30, y1 =15, y2 =?
x1/x2 = y2/y1
= 48/30 = y2/15
= y2 = 48X15/30
= y2 =24
24 workers is required.
(8) x1 =8, x2 =6, y1 =45, y2?
x1/x2 = y2/y1
= 8/6 = y2/45
= y2 = 45X8/6
Therefore, y2 =60 minutes.
(10) Then, a1 = x+1, a2 = x+2, b1 = x+1, b2 =?
a1/a2 = b2/b1
= x+1/x+2 = b2/x+1
= b2 = (x+1)2/x+2