Answer:
x ≥83%
Step-by-step explanation:
77%+x/2=80% (×b.s by 2)
77%+x=160%
x=160%-77%
x=83%
240 pints of blood (can you give me brainliest answer)
When they work together, it takes John 1/x hours and it takes Brian 1/(x+15) hours to complete 1/4 of the model.
1/x + 1/( x+15 ) = 1/4 / · x ( x+15 )
x+15 + x = x ( x+15 ) /4 / · 4
8 x + 60 = x² + 15 x
x² + 15 x - 8 x - 60 = 0
x² + 7 x - 60 = 0
x² + 12 x - 5 x - 60 = 0
x · ( x + 12 ) - 5 ·( x+ 12 ) = 0
( x + 12 ) · ( x - 5 ) =0
x = - 12 ( not accepted ) or x = 5
The time taken by Brian: 5 + 15 = 20 hours
Answer:
2.6
Step-by-step explanation:
