3)The original rational number was 17/12.
4)The age of Ruby and Reshma are 20 and 28 years respectively.
Explanation:
3)Let the numerator be x.
So denominator will be (x - 5)
If we add 5 to numberator then it will be (x + 5)
New number is (x + 5)/(x - 5)=11/6
Solve for X by cross multiplying
6(x + 5)=11(x - 5)
6x + 30=11x - 55
5x=85
x=17
So original rational number was 17/12.
4)The ages of Ruby and Reshma are in the ratio 5:7
So, let the present ages of Ruby and Reshma be 5x and 7x respectively.
Also, it is given that four years from now the ratio of their ages will be 3:4
So, the equation - 5x + 4 / 7x + 3 = 3/4
⇒4(5x+4)=3(7x+4)
⇒20x+16=21x+12
⇒21x−20x=16−12
⇒x=4
⇒5x=20 and 7x=28
The age of Ruby and Reshma are 20 and 28 years respectively.
Cost Price for oil change =$27
Charge for the customers =$40
Markup cost = Difference between selling price and cost price =$40-$27=$13
To find the percent of markup, divide the markup cost by the cost price and multiply it by 100.
Markup percent = (13/27)*100
=48.15%
<span>14.62 super simple, good luck with any other questions!</span>
Answer:

<h2>C. (13p+7) is the right answer.</h2>
For x=1: -7 x 1 + 4 = -3 y=-3
The ordered pair:(1, -3)
for x=3: -7 x 3 + 4 = -17 y=-17
The ordered pair:(3, -17)
for x=5: -7 x 5 + 4 = -35 y=-35
The ordered pair:(5, -35)
for x=7: -7 x 7 + 4 = -45 y =-45
The ordered pair:(7, -45)