Go through the Math in Focus Grade 5 Workbook Answer Key Chapter 5 Algebra to finish your assignments.

## Math in Focus Grade 5 Chapter 5 Answer Key Algebra

**Math Journal**

John’s solutions to the following problems are as shown. Identify and explain the mistakes John has made. Then give the correct solution.

Question 1.

4w + 12w – 10 = 16w – 10

= 6 w

Answer:

4w + 12w – 10 =** 16w – 10**

Explanation:

John has made a mistake in subtracting number from a variable type of number. So, the correct solution is 16w – 10.

Question 2.

20p – 2p + 4p = 20p – 6 p

= 14p

Answer:

20p – 2p + 4p = 24p – 2p = **22p**

Explanation:

John has made a mistake in the order of subtraction and additions. First we should add all the numbers and then subtract the numbers. So, the correct solution is 22p.

Question 3.

6 ÷ q = \(\frac{q}{6}\)

Answer:

6 ÷ q = **6/q**

Explanation:

John has made a mistake in putting the numerator and denominator of a division.

The number before the division symbol (÷) should be consider as numerator.

The number after the division symbol (÷) should be consider as denominator.

So, the correct solution is 6/q.

Question 4.

Clarissa bought 3 cartons of milk for y cents each. She gave the cashier $10. How much change did she receive? Express your answer in terms of y.

Answer:

3 × y = 3y

3 cartons of milk cost 3y cents.

$1 = 100 cents

So, $10 = 1,000 cents

Hence, Clarissa received (1,000 – 3y) cents in change.

**Put On Your Thinking Cap!**

**Challenging Practice**

Wendy bought 7 handbags. Each handbag costs the same amount. She paid the cashier $100 and received g dollars in change.

a. What was the cost of each handbag in terms of g?

Answer:

Total money paid to cashier is $100.

Total number of handbags bought = 7

Total change received = g $

So, cost of 7 handbags = (100-g)$

Cost of each handbag = (100-g)/7 $

b. If the price of each handbag was more than $1 0, what is the least possible value of g? (Assume that the cost of each handbag is a whole number.)

Answer:

Assume that each handbag costs 10$, then change given is (100-(7×10)) =(100-70)$ = 30$

Assume that each handbag costs 12$, then change given is (100-(7×12)) =(100-84)$ = 16$

Assume that each handbag costs 14$, then change given is (100-(7×14)) =(100-98)$ = 2$

So, the least possible value of g is 2.

**Put On Your Thinking Cap**

**Problem Solving**

There are 40 pupils in a class. There are x more girls than boys.

a. How many boys are there in terms of x?

Answer:

Let’s say total number of boys are ‘b’.

Then total number of girls in class will be ‘b+x’

Total number of pupils in class = number of boys + number of girls

40 = b + (b+x).

So, b=(40-x)/2

The number of boys in class un terms of ‘x’ is (40-x)/2

b. If x = 4, how many boys are there?

Answer:

As we know that number of boys = (40-x)/2

So, number of boys = (40-4)/2 = 36/2 =18

Therefore, total number of boys in class is 18.