4.7

a.	0.8 cycles/instruction = 5e9 cycles / 7.5e9 instructions * x

= 1.2 sec

b.	1.2 sec / 3 sec

= 40 %

4.9

A:	[(2 * 1) + 2 + 3 + 4 + 3] Cycles / (5 + 1) Instructions = 2.333 CPI
	2.333 CPI / 4 GHz = .583 nsec/inst

B:	[(2 * 2) + 2 + 2 + 4 + 4] Cycles / (5 + 1) Instructions = 2.667 CPI
	2.667 CPI / 6 GHz = .444 nsec/inst

	.583 nsec/inst / .444 nsec/inst

= 31.5% faster

4.11

	[1 sec * 1.e9 cycles/sec] / [2 cycles/instruction]

= 5e8 instructions

4.13

	{CPI, number of instructions in program, clock rate}
	{CPI, number of instrcutions in program, cycle time}
	{clock rate, number of cycles in program}
	{cycle time, number of cycles in program}
	{MIPS, number of instructions in program}