Sara can weed a garden in 30 minutes. When her brother Hamdan helps her, they can weed the same garden in 20 minutes. How long would it take Hamdan to weed the garden if he
worked by himself?

Step-by-step explanation:

It will take 42.35 minutes to weed the garden together.

Why?

To solve the problem, we need to use the given information about the rate for both Laura and her husband. We know that she can weed the garden in 1 hour and 20 minutes (80 minutes) and her husband can weed it in 1 hour and 30 minutes (90 minutes), so we need to combine both's work and calculate how much time it will take to weed the garden together.

So, calculating we have:

Laura's rate:

\frac{1garden}{80minutes}

80minutes

1garden

Husband's rate:

\frac{1garden}{90minutes}

90minutes

1garden

Now, writing the equation we have:

Laura'sRate+Husband'sRate=CombinedRateLaura

′

sRate+Husband

′

sRate=CombinedRate

\frac{1}{80}+\frac{1}{90}=\frac{1}{time}

80

1

+

90

1

=

time

1

\frac{1*90+1*80}{7200}=\frac{1}{time}

7200

1∗90+1∗80

=

time

1

\frac{170}{7200}=\frac{1}{time}

7200

170

=

time

1

\frac{17}{720}=\frac{11}{time}

720

17

=

time

11

\frac{17}{720}=\frac{1}{time}

720

17

=

time

1

\frac{17}{720}*time=1

720

17

∗time=1

time=1*\frac{720}{17}=42.35time=1∗

17

720

=42.35

Hence, we have that it will take 42.35 minutes to weed the garden working together.

answer: 7

step-by-step explanation: