The flight speed of the dragonfly is higher than the flight speed of the house fly by 260 / min and the flight

The flight speed of the dragonfly is higher than the flight speed of the house fly by 260 / min and the flight speed of the belyan-skit by 220 m / min. Find the flight speeds of these insects, taking into account that the doubled flight speed of the cabbage skit is 70 m / min less than the flight speed of the dragonfly.

Let us denote the flight speed of a dragonfly by the letter C, the flight speed of a fly by the letter M, and the flight speed of belyan-skit by the letter K. In accordance with the condition of the problem, we compose a system of equations:

C = M + 260;

C = K + 220;

2 x K = C – 70.

Substitute the expression for C from the second equation into the third:

2 x K = (K + 220) – 70;

2 x K = K + 220 – 70;

K = 150 (m / min).

Knowing K, one can easily find the speed of the dragonfly from the second equation:

C = 150 + 220;

C = 370 (m / min).

Now it remains to find the speed of the fly from the first equation:

M = C – 260;

M = 370 – 260;

M = 110 (m / min).

Answer: the flight speed of a fly is 110 m / min, a dragonfly is 370 m / min, and a belyana-kapustnik is 150 m / min.