Last year, Kala had $10,000 to invest. She invested some of it in an account that paid 7% simple interest per year, and she invested the rest in an account that paid 5% simple interest per year. After one year, she recelved a total of $620 in interest. How much did she invest in each account?

Suppose that the price p, in dollars, and the number of sales, x, of a certain item follow the equation 4 p plus 4 x plus 2 pxequals56. suppose also that p and x are both functions of time, measured in days. find the rate at which x is changing when xequals2, pequals6, and startfraction dp over dt endfraction equals1.5.