Question

x varies inversely as y, when x=15 then y=10, if x=20 then y=?​

Answer 1

Answer:

x varies inversely as y, when x = 15 then y = 10

if x = 20 then y = 7.5

Step-by-step explanation:

its given

x ∝ 1/y

x = k/y

=> xy = k

when x = 15 then y = 10

=> 15 * 10 = k

=> 150 = k

hence

xy = 150

if x = 20

then

20y = 150

=> 2y = 15

=> y = 15/2

=> y = 7.5

if x = 20 then y = 7.5

Answer 2

${\large{\bold{\sf{➠}}}}$${\large{\red{\sf{x}}}}$${\large{\bold{\sf{∝}}}}$${\large{\red{\sf{\frac{1}{y}}}}}$

${\large{\bold{\sf{➠}}}}$${\large{\red{\sf{\frac{x_{1}}{x_{2}}=\frac{y_{2}}{y_{1}}}}}}$

${\large{\bold{\sf{➠}}}}$${\large{\red{\sf{\frac{15}{20}=\frac{y_{2}}{10}}}}}$

${\large{\bold{\sf{➠}}}}$${\red{\sf{20×y_{2}=10×15}}}$

${\large{\bold{\sf{➠}}}}$${\large{\red{\sf{y_{2}=\cancel{\frac{150}{20}}}}}}$

${\large{\bold{\sf{➠}}}}$${\large{\red{\sf{y_{2}=7.5}}}}$