Train A:
Distance (s) = 420 miles
Time (t) = 3 hours
Speed (v) = distance ÷ time = 420 ÷ 3 = 140 miles/hour
Train B:
Distance (s) = 420 miles
Time (t) = 2.25 hours
Speed (v) = distance ÷ time = 420 ÷ 2.25 = 186.7 miles/hour
1) P=2w +2l
46=2w +14
32=2w
16= w or width
2) A=lw
A=7 x 12
A= 84
3) A= 12 x 21
A= 252
The answer is 8
Happy studying!
Hello from MrBillDoesMath!
Answer:
Take you pick below! (either x 8 or x = 7.01, approx, depending how the question is interpreted)
Discussion:
Interpretation 1
If the question is
2^(x -1) = 128, then as 2^7 = 128,
x-1 = 7 so x = 8
Interpretation 2
If the question is (2^x -1) = 128, then..
2^x = 128 + 1 = 129 =>
log(2^x) = log(129) =>
xlog(2) = log(129) =>
x = log (129) / log2 = 7.01
Regards,
MrB
