find odd natura number A such that lcm(A,40)equal to 1400

Answer 1

1400 = 200*7 = 2^3 * 5^2 * 7
40 = 2^3 * 5
But LCM(35,40) = 2^3*5*7 = 280
So, you want A = 5^2 * 7 = 175

Answer 2

X=175