Answer:
y = 15
Step-by-step explanation:
If the variables are directly proportional, increasing one by a factor of 3 will mean the other one also increases by a factor of 3.
6 is 3 times 2, so the value of y will be 3 times 5, or 15.
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You can write the relation as a proportion:
y/x = 5/2 = ?/6
Multiplying by 6 gives ...
(5/2)·6 = ? = 15
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Or, you can bother with an equation relating x and y:
y = kx
5 = k·2 . . . plug in the given values and solve for k
5/2 = k . . . divide by 2
Then ...
y = (5/2)·6 = 15 . . . . same as the proportion, above.
If you rearrange this to y = 5·(6/2) then you see the relation described at the beginning of this solution. The new value of y is the old value multiplied by the factor by which x changes.
