Answer:
Luke pays $12 for 28 bananas
The 28 bananas weigh 7 pounds
Step-by-step explanation:
First, let us find the weight of the 28 bananas. To do this, we first find the weigh of one banana and then multiply it by 28.
Now, we know that the weight of 7 bananas is 1 3/4 pounds; therefore, the weight of one banana is

To perform the above division, we first write the fraction in the numerator as an improper fraction.

and now the division becomes

Hence, one banana weigh 1/4 lb.
Therefore, 28 bananas weigh

Hence, we find that 28 bananas weigh 7 pounds.
Now, we find the cost of 28 bananas.
We know that 7 bananas cost $3.00; therefore, the unit price (cost per banana) is

Therefore, the price of 28 bananas will be

Hence, the price of 28 bananas is $12.