1. if to suppose the price of the apples is 'a' and the price of the grapes is 'g', then on the first day was earned 24*a+16*g=72.8 (1-equation) and on the second day 30*a+25*g=100.25 (2-equation);
2. if to solve these two equations as the the system of equations, then a=1.8 euro/kg and g=1.85 euro/kg
The answer is d (i.e. 51). the first 9 pages utilize 9 digits. the remaining 21 pages utilize two digits number. Therefore, 21*2=42 the total is 42+9=51
