You can get the tens digit of any number <em>n</em> by computing the quotient
(<em>n</em> (mod 100)) / 10
and ignoring the remainder.
Taking the given sum (mod 100) gives
7! + 8! + … + 2006! ≡ 7! + 8! + 9! (mod 100)
since the last 1997 terms (i.e. 10! up to 2006!) in the sum are multiples of 100. That is,
• every term beyond 100! is obviously a multiple of 100
• every term beyond 25! contains a factor of both 4 and 25
• every term beyond 10! contains two factors each of both 2 and 5 (i.e. every factorial term contains 4, 5, and 10)
The remaining sum is easy to compute by hand:
7! + 8! + 9! = 7! (1 + 8 + 8 × 9) = 5040 × 81 = 408,240
so the tens digit is 4.
So Abby hasn't received 60% of her order, BUT she already got 80 lobsters, hmmmmm well, 100% - 60% is just 40%, so she already got the 40%, which incidentally is 80 lobsters. Let's say the whole order, or 100% of it is "x" lobsters.
if 80 lobsters are 40%, what is "x"?
Answer:
22 cents
Step-by-step explanation:
Dividing 75 by 3 gets you 25. "Less than" as in subtracting, so subtract 3 from 25 and you get 22.
Answer:
7.4%
Step-by-step explanation:
find percentage of the tax
(total cost=$388.80)
28.80 out of 388.80
=28.80*100/388.8= 7.4%
