1.the ratio of a number to b number (10): (2 1) let a number be x and b number be y.x * 3/5 = y * 2/7 x/y = 2/7: 3/5 =/kloc-0. Let the area of the shaded part be 2x, then the area of the small circle is 5x and the area of the big circle is 14x. The ratio of the area of the big circle to the area of the small circle is 14x: 5x = 14: 53. Let Bank B be 6x and Party A be 10y. Then line A is 7x, and when Party B uses it, the speed of Party A is 9y = 7x/10y; The speed ratio of Party A and Party B is 7x/10y: 2x/3y = 21:20.