Final answer:
1. Dani's method: 7(t + b). 2. Chris's method: 7t + 7b. 3. Both methods are valid. 4. Total cost using Dani's method: $140. Total cost using Chris's method: $140. They can afford the gifts.
Step-by-step explanation:
Dani's Method:
The algebraic expression for Dani's method to find the total cost of the gifts is 7(t + b). This expression adds the cost of each shirt and the cost of each bag together, and then multiplies by seven.
Chris's Method:
The algebraic expression for Chris's method to find the total cost of the gifts is 7t + 7b. This expression multiplies the cost of each shirt by seven, multiplies the cost of each bag by seven, and then adds those two values together.
Comparison:
Both methods result in calculating the total cost of the gifts. However, Dani's method adds the costs together before multiplying by seven, while Chris's method multiplies each cost by seven and then adds them together. Both methods will yield the same answer as long as the individual costs are not different. Therefore, one method is not better than the other as long as the individual costs are consistent.
Total Cost:
Given that the tote bags cost $7.40 each and the t-shirts cost $12.60 each, we can calculate the total cost using both methods.
Dani's Method: Total Cost = 7(12.60 + 7.40) = 7(20) = $140
Chris's Method: Total Cost = 7(12.60) + 7(7.40) = 88.20 + 51.80 = $140
They can afford to buy these gifts as the total cost of $140 is less than the $150 they have in the bank.