An online data base charges $25 an hour during the day and $12.50 an hour at night. if a research company paid $250 for 12 hours of use, which system of equations could be used to determine the number of hours charged at the day rate (d) and at the night rate (n)?

a)
d + n = 12
25d + n = 250
b)
d + n = 12
25d + 12.50n = 250
c)
d − n = 12
25d + 12.50n = 250
d)
d + n = 250
25d − 12.50n = 250

ok then what happened.

0.02

step-by-step explanation:

time of 9 192 631 770 periods of the radiation corresponding to the transition between the 2 hyperfine levels of the ground state of the caesium 133 atom at 0 k (but other seconds are sometimes used in astronomy)

let y equal to

the total fare and x is the mile of taxi ride. so the equation is

y = 0.55x + 1.75

since susie has

$10 to spend for a taxi cab, so he can have

10 = 0.55x +

1.75

x = 15 miles of

taxi ride

so the system of

inequality is

10 < 0.55x +

1.75

x > 2