Calculating accumulated amount with effective interest and time as variables

Question

Given that i is an annual effective rate, 1 accumulates to 3 in r years, 2 accumulates to 7 in s years, and 3 accumulates to 16 in t years, I must determine what $10(1+i)^{(2r+s-t)}$ is equal to.

Answer 1

$(1+i)^r=3$

$2(1+i)^s=7$

$3(1+i)^t=16$

$10(1+i)^{2r+s-t}=10(1+i)^r(1+i)^r(1+i)^3/(1+i)^t=(10)(3)(3)(7/2)/(16/3)=59.0625$