# McGraw Hill Math Grade 5 Chapter 9 Lesson 4 Answer Key Units of Time

All the solutions provided in McGraw Hill Math Grade 5 Answer Key PDF Chapter 9 Lesson 4 Units of Time are as per the latest syllabus guidelines.

## McGraw-Hill Math Grade 5 Answer Key Chapter 9 Lesson 4 Units of Time

Solve
Question 1.
Jin spent 1$$\frac{1}{2}$$ hours doing her homework. How many minutes did she spend doing homework?
90 minutes she spend doing homework.

Explanation:
Number of hours Jin spent on doing her homework = 1$$\frac{1}{2}$$
Conversion:
1 hour = 60 minutes.
=> 1$$\frac{1}{2}$$  hours = 1$$\frac{1}{2}$$ × 60
= $$\frac{3}{2}$$ × 60
= 3 × 30
= 90 minutes.

Question 2.
Marsha jogged for 36$$\frac{3}{4}$$ minutes. Gary jogged for 28$$\frac{3}{5}$$ minutes. How much longer did Marsha jog in seconds?
489 longer Marsha jog in seconds.

Explanation:
Number of minutes Marsha jogged = 36$$\frac{3}{4}$$
Number of minutes Gary jogged = 28$$\frac{3}{5}$$
Difference:
Number of minutes Marsha jogged – Number of minutes Gary jogged
= 36$$\frac{3}{4}$$ – 28$$\frac{3}{5}$$
= [(144 + 3) ÷ 4] – [(140 + 3) ÷ 5]
= $$\frac{147}{4}$$ – $$\frac{143}{5}$$
= 36.75 – 28.6
= 8.15.
Conversion:
1 minute = 60 seconds
=> 8.15 minutes = 8.15 × 60
=> 489 seconds.

Question 3.
Samir spends 9 minutes a day brushing his teeth. If Samir does this every day, how many hours does he spend brushing his teeth in a year?
1,97,100 hours he spend brushing his teeth in a year.

Explanation:
Number of minutes Samir spends on brushing his teeth in a day = 9.
Conversion:
1 year = 365 days.
Number of minutes Samir spends on brushing his teeth in a year = Number of minutes Samir spends on brushing his teeth in a day × 365
=> 9 × 365
=> 3,285.
Conversion:
1 hour = 60 minutes.
=> 3285 minutes = 3285 × 60
=> 1,97,100 hours.

Question 4.
A red maple tree lives for an average of 70 years. What is the lifespan of a red maple tree in weeks?
3,744 weeks is the lifespan of a red maple tree in weeks.

Explanation:
Number of years a red maple tree lives for an average = 70.
Conversion:
1 year = 52 weeks.
=> 70 years = 70 × 52
=> 3,744 weeks.

Question 5.
Ms. Singh spends 72 months paying a car loan. Mr. Pedersen spends 48 months paying a car loan. How much longer does Ms. Singh pay for her loan in years?
2 years longer Ms. Singh pays for her loan in years.

Explanation:
Number of months Ms. Singh spends paying a car loan = 72.
Number of months Mr. Pedersen spends paying a car loan = 48.
Difference:
Number of months Ms. Singh spends paying a car loan – Number of months Mr. Pedersen spends paying a car loan
= 72 – 48
= 24.
Conversion:
1 year = 12 months.
=> 24 months = 24 ÷ 12
=> 2 years.

Question 6.
A box turtle named Houdini has lived at a zoo for 63 years. Another box turtle, named Kitt, has lived at the same zoo for 39 years. How many days in all have both turtles lived at the zoo? Use 365 days per year in your calculation.