The question should have said "..flying level...", That is at 1g. Lift is constant and is made up of CL and V squared, so if V has gone up to 1.3 times its Vs1g value then lift has gone up 1.3squared. CL then has to go down 1.3squared to compensate. 1.3squared is 1.69 and 1/1.69 (to get the final result) is 0.591 of the original value. The faster you go, the lower goes the nose.