Advertisements
Advertisements
Question
Car A travels x km for every litre of petrol, while car B travels (x + 5) km for every litre of petrol.
If car A use 4 litre of petrol more than car B in covering the 400 km, write down and equation in x and solve it to determine the number of litre of petrol used by car B for the journey.
Advertisements
Solution
Given Distance = 400 km
Car A travels x km/litre.
Car B travels (x + 5) km/litre.
Car A uses 4 litre more than car B
∴ `(400)/x - (400)/(x + 5)` = 4
400 (x + 5) - 400x = 4x(x + 5)
400x + 2000 - 400x = 4x2 + 20x
4x2 + 20x - 200 = 0
4 (x2 + 5x - 500) = 0
x2 + 25x - 20x - 500 = 0
x (x + 25) - 20 (x + 25) = 0
(x + 25) (x - 20) = 0
∴ x = 20 - 25 ...(inadmissible)
No. of litre of petrol used by car B
= `(400)/(20 + 5)`
= `(800)/(25)`
= 16.
RELATED QUESTIONS
`7x^2+3x-4=0`
Solve the following quadratic equations by factorization:
\[2x^2 + ax - a^2 = 0\]
If the equation 9x2 + 6kx + 4 = 0 has equal roots, then the roots are both equal to
If sin α and cos α are the roots of the equations ax2 + bx + c = 0, then b2 =
Solve the following equation : `"ax"^2 + (4"a"^2 - 3"b")"x" - 12"ab" = 0`
The length of a rectangle exceeds its breadth by 5 m. If the breadth were doubled and the length reduced by 9 m, the area of the rectangle would have increased by 140 m². Find its dimensions.
The perimeter of a rectangular plot is 180 m and its area is 1800 m2. Take the length of the plot as x m. Use the perimeter 180 m to write the value of the breadth in terms of x. Use the values of length, breadth and the area to write an equation in x. Solve the equation to calculate the length and breadth of the plot.
Solve the following equation by factorisation :
`sqrt(x + 15) = x + 3`
Car A travels ‘x’ km for every litre of petrol, while car B travels (x + 5) km for every litre of petrol.
- Write down the number of litres of petrol used by car A and car B in covering a distance of 400 km.
- If car A uses 4 litres of petrol more than car B in covering 400 km. write down an equation, in A and solve it to determine the number of litres of petrol used by car B for the journey.
At t minutes past 2 pm, the time needed by the minutes hand of a clock to show 3 pm was found to be 3 minutes less than `t^2/4` minutes. Find t.
