The simple interest i on an investment of p dollars at an interest rate r for t years is given by i = prt. find the time it would take to earn $900 in interest on an investment of $21,000 at a rate of 4.6%.

Linda loans her friend $250 with a 5% monthly intrest rate. how much was the whole loan?

Graph the equationy=x^2 -[tex]y = x^{2} - 2[/tex]

Lizette is training for a marathon. at 7: 00 she left her house and ran until 8: 30, then she walked until 11: 30. she covered a total distance of 18 miles. her running speed was six miles per hour faster than her walking speed. find her running and walking speeds in miles per hour.