90% of what is 63....
0.90x = 63
x = 63 / 0.90
x = 70....so 70 ppl work at stalling printing
The total number of keys equals:
12 + 5 + 11 + 2 = 30 keys
The probability to pick a sliver key is:
12/30 = 2/5
The probability to pick a copper key is:
11/30
Hope that helps
2.9. The seven is able a five, so you round up to the next number.
0.13 is the answer
Hoped that helps:)
