Select the set of equations that represents the following situation: Mary invested one amount at 7% simple interest, and a second amount at 5% interest, earning $29.80 in one year. If she had switched the amounts, she would have earned $35.00. What were the two amounts?
(Points : 3)
0.07x + 0.05y = 29.80; 0.07y + 0.05x = 35.00
7x + 5y = 29.80; 7y + 5x = 35.00
0.07x + 0.05y = 35.00; 0.07x + 0.05y = 29.80
7x + 5y = 35.00; 7x + 5y = 29.80
Check your 2-22-11,10:36am post.
To solve this problem, we need to set up a system of equations based on the given information. Let's call the first amount that Mary invested 'x' and the second amount 'y'.
According to the problem, Mary earned $29.80 in one year when she invested the first amount at 7% simple interest and the second amount at 5% interest. This can be expressed by the equation: 0.07x + 0.05y = 29.80.
If Mary had switched the amounts, she would have earned $35.00 in one year. This situation can be represented by the equation: 0.07y + 0.05x = 35.00.
So, the correct set of equations that represents the given situation is:
0.07x + 0.05y = 29.80;
0.07y + 0.05x = 35.00.
Therefore, the answer is: 0.07x + 0.05y = 29.80; 0.07y + 0.05x = 35.00.