Consider program p1, which runs on a 2GHz computer M in 20 seconds.?

An optimization is made to p1, replacing all instances of multiplying a value by 5 (Multi x,x,5)with two instructions (SLL Y,x,2; ADD X,X,Y). Call this new program P2. The CPI for multiply instruction is 10 and the CPI of a SLL and a ADD is 3.After recompiling, P2 now runs in 15 seconds on computer M. How many MULTI instructions were replaced by the new compiler?