Meena, a machinist, wants to cut a shaft down to a diameter of 1 5/16 inches. How much must Meena decrease the shafts diameter if it now measures 1 7/8 inches?
-
1 5/16 = (16 + 5)/16 = 21/16
1 7/8 = (16 + 2*7)/16 = 30/16
Difference = (30 - 21)/16 = 9/16 <<<
1 7/8 = (16 + 2*7)/16 = 30/16
Difference = (30 - 21)/16 = 9/16 <<<
-
The formula is (Inches to cut = Current length - Desired Length) (Also I am ignoring the 1 in front b/c it's not necessary for the answer)
The current length is 7/8" = 14/16"
so then...
Inches to cut = 14/16 - 5/16 = 9/16 which is your answer of how much to cut off from the diameter.
The current length is 7/8" = 14/16"
so then...
Inches to cut = 14/16 - 5/16 = 9/16 which is your answer of how much to cut off from the diameter.
-
Find the common denominator of the fractional parts:
convert the mixed fractions to improper fractions:
1 5/16 = 16/16 + 5/16 = 21/16
1 7/8 = 8/8 + 7/8 = 15/8
15/8 can be expressed as something over 16 if you multiply it by 2/2 (which is a nother way of saying 1, since we are multiplying by 1, we are not changing the fraction)
15/8 * 2/2 = 30/16
Now we can subtract:
30/16 - 21/16 = 9/16
convert the mixed fractions to improper fractions:
1 5/16 = 16/16 + 5/16 = 21/16
1 7/8 = 8/8 + 7/8 = 15/8
15/8 can be expressed as something over 16 if you multiply it by 2/2 (which is a nother way of saying 1, since we are multiplying by 1, we are not changing the fraction)
15/8 * 2/2 = 30/16
Now we can subtract:
30/16 - 21/16 = 9/16