Question

If x varies directly as y, and x = 7.5 when y = 10, find x when y = 4

Answer 1

7.5=10k
so find k

Answer 2

then once you find k, insert k into this equation, and then do x=k4

Answer 3

can you explain please

Answer 4

so did you find k?

Answer 5

i dont know this type of mathematics need to learn them some are just to hard

Answer 6

okay this is a direct variation problem and the way to understand direct variation is (for example) if y varies directly as x which makes the formula y=kx
k is the variable constant
and then they normally say if y varies directly as x, when y=1 and y=1.
so lets practice what would that equation look like?

Answer 7

y=1x

Answer 8

no it would be 1=1k because the formula is y=xk remember so you replace the x and y with a one

Answer 9

sorry i mean solve for k

Answer 10

oh

Answer 11

so what would k equal?

Answer 12

k=1

Answer 13

wrong right

Answer 14

good! so your problem said that x varies directly as y, and x=7.5 when y=10.
so what would that look like? we will do the second part later

Answer 15

k=10

Answer 16

x=ky
7.5=10k

Answer 17

no k will not equal 10

Answer 18

i see what your trying to say but i dont get it

Answer 19

okay so k would equal 0.75
then do x=4(0.75)
then you will find the answer

Answer 20

3