The rearrangement of cyclopropane to propene at $500C$

$(C{H}_2{)}_{3}longrightarrowC{H}_{3}CH=C{H}_2$

is first order in $(C{H}_2{)}_3$ with a rate constant of $0\mathrm{.}000670s^{-1}.$

If the initial concentration of $(C{H}_2{)}_3$ is $0\mathrm{.}151M,$ the concentration of $(C{H}_2{)}_3$ will be $0\mathrm{.}0245M$ after