Given a math problem with context and a question and 5 answer choices, the task is to provide the correct answer choice based on the problem. You must choose one of the given answer choices by letter: a, b, c, d, or e; anything else is invalid.

Q: Problem: a grocer has a sale of rs. 5420, rs. 5660, rs. 6200, rs. 6350 and rs. 6500 for 5 consecutive months. find the sale he should have in the sixth month, so that he gets an average sale of rs. 6400 ?
Options: a. rs. 5870, b. rs. 8270, c. rs. 6020, d. rs. 6850, e. none of these

A: b
****
Q: Problem: a sells a bicycle to b and makes a profit of 50 %. b sells the same bicycle to c at a profit of 25 %. if the final s. p. of the bicycle was rs. 225, find out the cost price of the bicycle for a.
Options: a. 237, b. 126, c. 971, d. 611, e. 120

A: e
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Q: Problem: a tempo, while travelling at 70 kmph, uses 30 % more petrol than it uses while travelling at 50 kmph for travelling a certain distance. using one litre of petrol, it can travel 19.5 km at 50 kmph. how far can the tempo travel on 10 litres of petrol at a speed of 70 kmph ?
Options: a. 150 kms, b. 160 kms, c. 170 kms, d. 180 kms, e. 190 kms

A:
a
****