Can anyone explain why my method doesn’t work? Here, I found the rate for A as 0.5, then found the rate for B as 1p/x hrs. Then I found the combined rate as 1p = r (45 min). I multiplied that by 60 min to get the combined rate as 1.3 hours. Then I did 1.3 hrs - 0.5 hrs to get 0.8 hours for B.
The approach is the same.
There is one error in the math
You have the rates for A and B as 0.5 and 1/x respectively
Hence the combined rate is (0.5 + 1/x)
You got a value of 1.3 (the decimal form of 4/3 approximated) as the combined rate
So 1.3 should = (0.5 + 1/x)
1/x = 1.3 - 0.5
1/x = 0.8
X = 1/0.8 = 1.25
Which is not the same as Greg’s answer of 6/5 (which is equal to 1.2) but only because of the approximation that was done (1.333 ~ 1.3)
Pro tip:
Keeping the equations in fractions in this case would have made the math easier to follow
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Thank you!
You’re welcome