(2) if the difference between the two commercialand valid interestis 15 riyals fora certain amount invest fora period 151 days, with an interest rate of 6% per annum, find the value of this amount? (3) A trader invested an amount from 01/04/2013 to 04/20 of the same year at a rate of 9% annually and the dfference between the two commercaland valid interests was riya's forthe same period and the same rate Find the origin of the amount