A student, who is also working home-office as a web designer received a $500 payment at the end of January. At the end of February, she spent this $500 and an additional S1500 to buy a computer. Later, she earns $500 and $1250 at the end of March and April, respectively. Her conclusion was that over the 4 months, she had received $250 more than she spent. Determine if the student has a multiple ROR situation for these cash flows. If so, determine the multiple rates and comment on their validity.