Let A, B, C represent their respective weights. Then, we have:
A + B + C = (45 x 3) = 135 .... (i)
A + B = (40 x 2) = 80 .... (ii)
B + C = (43 x 2) = 86 ....(iii)
Adding (ii) and (iii), we get: A + 2B + C = 166 .... (iv)
Subtracting (i) from (iv), we get : B = 31
B's weight = 31 kg.
There are two sections A and B of a class, consisting of 36 and 44 students
respectively. If the average weight of sections A is 40 kg and that of section b is 35
kg. Find the average weight of the whole class?
Distance between two stations A and B is 778 km. A train covers the journey from
A to B at 84 km per hour and returns back to A with a uniform speed of 56km per
hour. Find the average speed of the train during the whole journey?