Thread: [SOLVED] SAT math page 737 #16

If what happens to the value of y when both x and z are doubled?

a) y is not changed
b) y is halved
c) y is doubled
d) y is tripled
e) y is multiplied by 4

when both the denominator and numerator are both doubled doesn't it both cancel out and therefore y remains the same?

Thanks in advance

Originally Posted by fabxx

If what happens to the value of y when both x and z are doubled?

a) y is not changed
b) y is halved
c) y is doubled
d) y is tripled
e) y is multiplied by 4

when both the denominator and numerator are both doubled doesn't it both cancel out and therefore y remains the same?

Thanks in advance

replace x and z with 2x and 2z respectively. what happens to the y-value?

Originally Posted by Jhevon

replace x and z with 2x and 2z respectively. what happens to the y-value?

I got
which is the same as isn't it? But how come the correct answer is e) y is multiplied by 4?

Originally Posted by fabxx

I got
which is the same as isn't it? But how come the correct answer is e) y is multiplied by 4?

that is because is not what you're supposed to get. i said replace x with 2x and z with 2z. what you did was multiply by 2/2, which is 1, of course you got the same thing back

grr. I still don't get it. Doesn't the question say to double BOTH x and z?

Originally Posted by fabxx

grr. I still don't get it. Doesn't the question say to double BOTH x and z?

yes. that means you change x to 2x and z to 2z as i have been saying

thus and

when it is all said and done, we have

thus y is multiplied by 4