Answer:
<em>24 children</em>
Step-by-step explanation:
If the length of time, y hours, it takes to put a jigsaw puzzle together is inversely proportional to the number of children, x, this is represented as;
k is the constant of proportionality
If it takes 16 children 6 hours to put the jigsaw puzzle together, this means at x = 16, y = 6
Substitute:
6 = k/16
k = 6*16
k = 96
W are to find number of children needed to put the same jigsaw puzzle together in 4 hours, this is done by substituting k = 96 and y = 4 into the expression y = k/x
y = 96/4
y = 24
<em>Hence it will take 24 children to put the same jigsaw puzzle together in 4 hours</em>
<em></em>
You can simply collect terms, subtract the constant and divide by the x-coefficient. It is generally considered easier to do those steps if you eliminate fractions first (multiply by 12).
Multiply by 12
... 4(x -1) +3(x +5) = 6
... 4x -4 +3x +15 = 6 . . . . . eliminate parentheses
... 7x +11 = 6 . . . . . . . . . . . .collect terms
... 7x = -5 . . . . . . . . . . . . . . subtract the constant 11
... x = -5/7 . . . . . . . . . . . . . divide by the x-coefficient
_ _ _ _ _ _ _
Here it is the other way.
... x(1/3 +1/4) +(-1/3 +5/4) = 1/2
... (7/12)x + 11/12 = 1/2 . . add the fractions to finish collecting terms
... x + 11/7 = 6/7 . . . . . . . multiply by 12/7
... x = -5/7 . . . . . . . . . . . subtract 11/7
At the third step here, you could subtract 11/12 before doing the multiply. You get the same answer, but you have to do the extra conversion of 1/2=6/12.
66 minutes is the correct answer
Answer:
D
Step-by-step explanation:
