Exercise 1 Page 181

We want to find the cost of the camera. To do so, we will use the percent equation. part = percent * whole We are told that Sharon paid $ 78 sales tax on the camera and it is 6.5 % of the total cost. Let's draw a bar diagram to represent the problem. In the diagram, let c represent the cost of the camera.

Now we will apply the percent equation to the given situation. For simplicity, we can temporarily ignore the units. part = percent * whole [0.4em] ↓ [0.4em] 78 = 6.5 % * c We need to write the percent as a decimal before we can solve the equation that we got. To write a percent as a decimal, we will ignore the percent symbol and move the decimal point two places to the left.

Therefore, 6.5 % is equal to 0.065. 78 = 6.5 % * c [0.4em] ↓ [0.4em] 78 = 0.065 * c Finally, we will solve the equation for c.

78=0.065* c

DivEqn

.LHS /0.065.=.RHS /0.065.

78/0.065=0.065* c/0.065

CancelCommonFac

Cancel out common factors

78/0.065=0.065* c/0.065

SimpQuot

Simplify quotient

78/0.065=c

UseCalc

Use a calculator

1200=c

RearrangeEqn

Rearrange equation

c=1200

We got that c= 1200 is a solution to the equation. This means that the cost of the camera is equal to $ 1200.