Chapter 1.7, Problem 32CCR

(a)

To determine

The number of nickels in any number of dollars n

Answer to Problem 32CCR

  $\left(ii\right)1-{\cos }^{2}u$

Explanation of Solution

Given:

There are 20 nickels in one dollar .

Concept Used:

• To get rid of a number in addition from one side, subtract the same number from both sides of equal sign.
• To get rid of a number in subtraction from one side, add the same number both sides of equal sign.
• To get rid of a number in multiplication from one side, divide the same number from both sides of equal sign.
• To get rid of a number in division from one side, multiply the same number both sides of equal sign.

Rules of Addition/ Subtraction:

• Two numbers with similar sign always get added and the resulting number will carry the similar sign.
• Two numbers with opposite signs always get subtracted and the resulting number will carry the sign of larger number.

Calculation:

In order to find the number of nickels in n dollars $\text{1}\text{dollar}=\text{20 nickels }$ , use the unitary method with the given scale and simplify further as shown below,

  $\begin{array}{l}\text{1}\text{dollar}=\text{20 nickels }\\ n\text{dollars}=20n\end{array}$

Thus, the number of nickels in n dollars is. $n\text{dollars}=20n$

(b)

To determine

The numbers of nickels in $7.00

Answer to Problem 32CCR

The number of nickels in $7.00 is $140$ .

Explanation of Solution

Given:

  $\text{1}\text{dollar}=\text{20 nickels }$

Calculation:

In order to find the number of nickels in $7.00 dollars, use the unitary method with the given scale and simplify further as shown below,

  $\begin{array}{c}\text{1}\text{dollar}=\text{20 nickels }\\ 7\text{dollar=20}\times \text{7}\\ \text{=140}\end{array}$

Thus, the number of nickels in $7.00 is $140$ .