x= 4,5,6. y=10,12,14 solve by direct proportion
Answers
Answer:
Question 1:
Write the following statements using the symbol of variation.
(1) Circumference (c) of a circle is directly proportional to its radius (r).
(2) Consumption of petrol (l) in a car and distance travelled by that car (d) are in direct variation.
ANSWER:
(1)
Circumference (c) of a circle is directly proportional to its radius (r). This statement is written as
c∝r
(2)
Consumption of petrol (l) in a car and distance travelled by that car (d) are in direct variation. This statement is written as
l∝d
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Question 2:
Complete the following table considering that the cost of apples and their number are in direct variation.
Number of apples (x) 1 4 ... 12 ...
Cost of apples (y) 8 32 56 ... 160
ANSWER:
It is given that the cost of apples (y) and number of apples (x) are in direct variation.
∴y∝x⇒y=kx, where k is constant of variation
When x = 1, y = 8.
∴ 8 = k × 1
⇒ k = 8
So, the equation of variation is
y = 8x
When y = 56,
56 = 8x
⇒ x = 7
When x = 12,
y = 8 × 12 = 96
When y = 160,
160 = 8x
⇒ x = 20
The complete is given below.
Number of apples (x) 1 4 7 12 20
Cost of apples (y) 8 32 56 96 160