tens digit = t ones digit = u number = 10t+u the ones digit multiplied by five and the tens digit by three and the result added = 5u+3t
Divide both sides by 4t The only digits in the ratio u:t = 7:4 are u=7 and t=4. So the number is 47. Checking: 5×7+3×4 = 35+12 = 47 Edwin