Telanagana SCERT Solution Class VIII (8) Math Chapter 10 Direct and Inverse Proportions Exercise 10.2
(1) (i)
x | 50 | 40 | 30 | 20 |
y | 5 | 6 | 7 | 8 |
x1 y1 = 50X5 =250
x2 y2 = 40X6 =240
x3 y3 = 30X7 =210
x4 y4 = 20X8 =160
So, it is not inversely proportional.
(ii)
x | 100 | 200 | 300 | 400 |
y | 60 | 30 | 20 | 15 |
x1 y1 = 100X60 =6,000
x2 y2 = 200X30 =6,000
x3 y3 = 300X20 =6,000
x4 y4 = 400X15 =6,000
So, it is inversely proportional.
(iii)
x | 90 | 60 | 45 | 30 | 20 | 5 |
y | 10 | 15 | 20 | 25 | 30 | 25 |
x1 y1 = 90X10 =900
x2 y2 = 60X15 =900
x3 y3 =45X15 =90
x4 y4 = 30X25 =750
x5 y5 = 5X25 =75
So, it is not inversely proportional.
(2) Total amount for purchasing book is 6000.
So,
Price of each books | 40 | 50 | 6000/100 =60 | 75 | 6000/75 =80 |
Number of books that can be purchased | 150 | 6000/50 =120 | 100 | 6000/75 =80 | 75 |
(3)
No of Rows (R) | 2 | 3 | 4 | 6 | 8 |
No of columns (C) | 48/2 =24 | 48/3 =16 | 12 | 8 | 48/8 =6 |
(I) Yes 2:3 = 16:24
(ii) Yes 4:6 = 8:12
(iii) Obviously yes since 2X24 =48, 3X16 =48…… 8X6=48.