If y varies directly as x and y = 10 when x = 2, what is y when x = 3?

2 Answers
Apr 24, 2018

#y = 15#

Explanation:

Given

#y ∝ x#

#y = kx#

When #y = 10#, #x = 2#

#10 = k × 2#

#k = 10/2#

#k = 5#

When #x = 3#

#y = k × 3#

#y = 5 × 3 = 15#

Apr 24, 2018

#y=15#

Explanation:

#"the initial statement is "ypropx#

#"to convert to an equation multiply by k the constant"#
#"of variation"#

#rArry=kx#

#"to find k use the given condition"#

#y=10" when "x=2#

#y=kxrArrk=y/x=10/2=5#

#"equation is " color(red)(bar(ul(|color(white)(2/2)color(black)(y=5x)color(white)(2/2)|)))#

#"when "x=3" then"#

#y=5xx3=15#