Since Irina can paint 1 room in 9 hours, that means she paints 1/9 of the room in 1 hour. Her portion of the equation would be 1/9x, with x being the number of hours she works and 1/9 of a room per hour being her speed.
Since Paulo can paint 1 room in 8 hours, that means he paints 1/8 of the room in 1 hour. His portion of the equation would be 1/8x, with x being the number of hours he works and 1/8 of a room per hour being his speed.
The equation would then be 1/9x + 1/8x = 1 (Irina's portion of the room, plus Paulo's portion of the room, equal to one whole room).
Find a common denominator. 72 is the first number that both 9 and 8 divide evenly into. Since 9*8 = 72, we multiply the top of 1/9 by 8 to convert the fraction and get 8/72x. Since 8*9 = 72, we multiply the top of 1/8 by 9 to convert the fractio and get 9/72x. We now have 8/72x+9/72x=1
17/72x=1
Divide both sides by 17/72:
17/72x ÷ 17/72 = 1÷17/72
x=1/1 ÷ 17/72
x=1/1 * 72/17
x=72/17=4.24
Together it should take them 4.24 hours.
Answer:
0.99804932311
Step-by-step explanation:
We solve this using binomial probability
Binomial probability formula
= nCx × p^x × q^n - x
= n!/(n - x)! x!
Where n = Number of trials = 25 samples
x = Number of successes = 23
p = probability of success = 99% = 0.99
q = probability of failure = 1 - p
= 1 - 0.99
= 0.01
Hence,
p(at least 23 are properly filled) = p(X ≥ x)
= [25!/(25 - 23)! × 23! × 0.99^23 × 0.01^25 - 23 ]+ [25!/(25 - 24)! × 24! × 0.99^24 × 0.01^25 - 24 ]+ [25!/(25 - 25)! × 23! × 0.99^25 × 0.01^25 - 25]
= [300 × 0.99 ^23 × 0.01^2] + [25 × 0.99^24 × 0.01^1] + [1 × 0.99^25 + 0.01^0]
= 0.0238084285 + 0.1964195352 + 0.7778213594
= 0.99804932311
Answer: Answer is 40 just add them all up and there’s your answer :) brainliest please
Step-by-step explanation:
Answer:
27
Step-by-step explanation:
18+19=27
