If you multiply 5.06 by 47.058 you will get 238.11348
You're going to want to take the total, which is $353.00 and subtract the initial cost, which is $84.00, the number now should be $269. Using that total divide it by $68.00, there you should find your answer of about 4 hours. The precise answer is 3.99588235. But you would round that to 4 hours.
About 379.1666666666666
The 6 is repeating. Or about 379 if your rounding.
2.5 pounds of grain cost ======= $1.75
∴ 5.3 pounds of grain will cost ===== (5.3×1.75)/2.5 = $3.71
