Solve.
-When making a telephone call using a calling card, a call lasting 5 minutes cost $\$ 0.90$. A call lasting 12 minutes cost $\$ 1.60$. Let $y$ be the cost of making a call lasting $x$ minutes using a calling card. Write a linear equation that models the cost of making a call lasting $x$ minutes.
A) $y = 0.1 x + 0.4$
B) $y = 10 x - \frac { 491 } { 10 }$
C) $\mathrm { y } = - 0.1 \mathrm { x } + 1.4$
D) $\mathrm { y } = 0.1 \mathrm { x } - 10.4$

Question

Quizplus · Accepted Answer

To find the linear equation, we can use the two given points: (5, 0.90) and (12, 1.60). The slope $m$ is calculated as $\frac{1.60 - 0.90}{12 - 5} = \frac{0.70}{7} = 0.1$. To find the y-intercept $b$, we can use one of the points, for example, $0.90 = 0.1(5) + b$, solving for $b$ gives $b = 0.90 - 0.5 = 0.4$. Thus, the equation is $y = 0.1x + 0.4$.

Solve -When Making a Telephone Call Using a Calling Card $0.90\$ 0.90$0.90

Solve
-When Making a Telephone Call Using a Calling Card $\$ 0.90$