Aptitude - Average - Discussion

Discussion Forum : Average - General Questions (Q.No. 9)
9.
A car owner buys petrol at Rs.7.50, Rs. 8 and Rs. 8.50 per litre for three successive years. What approximately is the average cost per litre of petrol if he spends Rs. 4000 each year?
Rs. 7.98
Rs. 8
Rs. 8.50
Rs. 9
Answer: Option
Explanation:

Total quantity of petrol
consumed in 3 years
= 4000 + 4000 + 4000  litres
7.50 8 8.50
= 4000 2 + 1 + 2  litres
15 8 17
= 76700  litres
51

Total amount spent = Rs. (3 x 4000) = Rs. 12000.

Average cost = Rs. 12000 x 51 = Rs. 6120   = Rs. 7.98
76700 767

Discussion:
92 comments Page 4 of 10.

Ramsreeram said:   1 decade ago
Its simple because answer must be close to 7.98 or 8 here averages so it must be ratio form so 7.98.

Nitesh bhati said:   1 decade ago
1st year 4000/7.5 = 533.3.

2nd year 4000/8 = 500.

3rd year 4000/8.50 = 470.5.

= 533.3+500+470.5 = 1503.8.

= 1503.8*7.98 = 4000*3.

= 12000 = 12000.

LHS = RHS.
(1)

Jobin said:   1 decade ago
Normally average will be Rs. 8 if we won't take the factor of Rs. 4000 per year. When we consider the amount per year, number of liter consumed in the 1st year will be more than second and third.

So approximately the average will be less than 8 and greater than 7.5. And more nearer to 8. So the answer is 7.98.
(1)

Gunwanti said:   1 decade ago
Can any one explain 76700/51?

Abhishek said:   1 decade ago
Where 51 came from?

Gameruler said:   10 years ago
How can we calculate this without using the calculator?

Jeevan j said:   10 years ago
At most one minute is the time available for this question. So further simplifications is required.

Subhasmita said:   10 years ago
Please solve this equation 4000(2/15+1/8+2/17) = ?

Mounika said:   10 years ago
Answer: 1503.92.

Henry said:   10 years ago
When you say approximately. Is it wise to say the answer is 7.98 instead of 8.0 which is B?


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