The minimum fine for driving in excess of the speed limit is $25. An additional $6 is added to the minimum fine for each mile per hour (mph) in excess of the speedlimit. Rachel was issued a $103 fine for speeding in a 55-mph speed limit zone. For driving at what speed, inmph, was Rachel fined?

Sagot :

Let the excess speed limit be y.

According to your question,

25 + 6y = 103

6y = 103 - 25 = 78

y = 78/6 = 13

Thus, the excess speed was 13 mph.

Thus, speed of Rachel = 55 + 13 = 68mph

Thus, Rachel was driving at 68 mph.

When total fine is $103 and speed limit is 55 mph then rachel was driving at 68mph

What is linear equation ?

A equation of order 1 is called linear equation .

Given that a minimum fine of $25 fixed

And Additional fine is $6 for each mile per hour

Let suppose Rachel was driving at  y mph more than speed limit

Now we can write expression of total fine as

Total fine = 6+25y

Given that total fine is 103

So we can calculate y as

103= 25+6y

Now simplifying this linear equation

103-25=6y

78=6y

y=13

Given that speed limit was 55mph

Hence Rachle's speed = 55+13=68 mph

When total fine is $103 and speed limit is 55 mph then rachel was driving at 68mph

To learn more about linear equations visit :https://brainly.com/question/2263981