too find the ratio a:b, first calculate the values of m and n using the given ratio m:n = 2:5. This means m = 2 and n = 5.
Next, substitute the values of m and n in the second ratio a:b = 10m:3n.
This gives us a:b = 10 * 2 : 3 * 5 = 20:15 = 4:3.
Therefore, the ratio a:b is 4:3.
