Problem $5$:

You are going to enhance a computer, and there are two possible improvements: either make multiply instructions

run three times faster than before or make memory access instructions run four times faster than before. You

repeatedly run a program that takes $400$ seconds to execute. Of this time, $25\%$ is used for multiplication, $35\%$ for

memory access instructions, and $40\%$ for other tasks. What will the speedup be if you improve only multiplication?

What will the speedup be if you improve only memory access? What will the speedup be if both improvements are

made? Use Amdahl's law.