SOLUTION: Please help me solve this problem: 1/a+1/b=1/C if a=10 and c=4. Find b.

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Question 132938: Please help me solve this problem:
1/a+1/b=1/C if a=10 and c=4. Find b.
Answer by MathLover1(20849) About Me  (Show Source):
You can put this solution on YOUR website!
1%2Fa%2B1%2Fb=1%2FC
if a=10 and c=4, then
1%2Fb=1%2FC+-%281%2Fa%29
1%2Fb=%28a+-C%29%2FCa%29.....cross multiply
Ca+=b%28a+-C%29+
+b=C%2Aa%2F%28a+-C%29....plug in values for a and C
+b=%284%2A10a%29%2F%2810+-4%29....

+b=%2840%2Aa%29%2F6....

b=6.6666666666666666666666666666667
b=6.7
check:
1%2Fa%2B1%2Fb=1%2FC
1%2F10%2B1%2F6.7=1%2F4

0.1%2B0.15=0.25
0.25=0.25