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 assume x represents the amount Mary invested at 7% interest, and y represents the amount she invested at 5% interest.
From the problem, we know that the total interest earned in one year is $29.80. This means that we can set up the first equation as:
0.07x + 0.05y = 29.80
Similarly, we are given that if Mary had switched the amounts, she would have earned $35.00. This implies the second equation:
0.07y + 0.05x = 35.00
So, the correct set of equations representing the situation is:
0.07x + 0.05y = 29.80;
0.07y + 0.05x = 35.00