Earnest T needs $$820$ for his next trip to Raleigh. He has $$520$ in cash. How long in years will

it take the $$520$ cash to grow to $$820$ if Earnest T earns $9\mathrm{.}6\%$ per annum on his cash,

compounded quarterly? $($Enter your answers in years to $2$ decimal places, e$.$g$.,12\mathrm{.}34)$