A garage owner bought a certain number of litres of petrol for sh 760. If the petrol cost sh x per litre........

      

A garage owner bought a certain number of litres of petrol for sh 760. If the petrol cost sh x per litre
a) write down an expression for the number of litres of petrol he obtained
b) When the price per litre was up by 25 cents he found that he obtained 5 litres fewer for the same sum of money
i) Form an equation in x and show that it reduces to 4x2 + x – 95 = 0
ii) Solve the equation and calculate the price of petrol after the rise

  

Answers


John
a) Number of litres bought

= $\frac{760}{x}$

b) Number of litres bought when the price was up

$\frac{760}{x + \frac{1}{4}}$ = $\frac{760}{\frac{4x + 1}{4}}$

= $\frac{760}{4x + 1}$

= $\frac{760}{x} - \frac{3040}{4x + 1}$ = 8

= $\frac{760(4x + 1) – x(3 040)}{x(4x + 1)}$ = 8

760 = 32x2 + 8x

95 = 4x2; + x

Therefore 4x2 + x – 95 = 0

c) 4x2 + x – 95 = 0

P = -380

S = 1

N = 20,-19

(4x2 - 19) (x + 5) = 0

4x – 19 = 0; 4x = 19

X = sh 4. 75

Price after the rise was

Sh 4. 75 + 0.25

= sh 5.00
johnmulu answered the question on March 6, 2017 at 05:48


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