Interesting Speedup & Amdahl's law problem
You can calculate the speedup in MFLOPs. Speedup is a dimensionless quantity, so you don't need to know the execution time to calculate it.
You need to know the old execution time only if you need to find out the improved execution time.

In this problem, we can calculate the increase in MFLOPS by dividing the ratio of Floating point instructions to total number of instructions after improvement by the ratio of Floating point instructions to total number of instructions before improvement, since the Cycles Per Instruction is 1 and clock cycle time remains the same.
Increase in MFLOPS = $\dfrac{(Ratio\ of\ Floating\ point\ instructions\ to\ total\ number\ of\ instructions\ after\ improvement)} {(Ratio\ of\ Floating\ point\ instructions\ to\ total\ number\ of\ instructions\ before\ improvement)} $