Question #14d05

2 Answers
Dec 1, 2017

#x = 7.5#

Explanation:

We know that #y# is proportional to #x#, so #yproptox=>y=kx#. This tells us that #y/x=k#, where #k="a constant"#.

So, we know that #y_1/x_1=y_2/x_2# which becomes #40/4=75/x_2#

By a process of rearranging we get: #x_2=(75*4)/40=75/1*4/40=75/1*1/10=75/10=7.5#

#x=7.5#

Hope this helps!

Dec 1, 2017

#x=7.5#

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=40" when "x=4#

#y=kxrArrk=y/x=40/4=10#

#• " equation is "y=10x#

#"when " y=75#

#rArrx=y/10=75/10=7.5#