Me find the volume of ring (cylinder)

What will be the ratio of petrol and kerosene in the final solution formed by mixing petrol and kerosene that are present in three identical vessels in the ratio 4: 1,5: 2 and 6 : 1 respectively?

Aboy is standing on the ground and flying a kite with 100m of string at an elevation of 30. another boy is standing on the roof of a 10m high building and is flying his kite at an elevation of 45. both the boys are on opposite sides of both the kites. find the length of the string that the second boy must have so that the two kites meet.

587 × 108 miles, (b) 587 × 1010 miles, (c) 587 × 10-10 miles, (d) 587 × 1012 miles, (e) 587 × 10-12 miles