Answer:
10 minutes
Step-by-step explanation:
Let's use the variable x for the amount of coins.
The first machine can sort x coins in 15 minutes, so its speed is x/15 coins/minute.
The second machine can sort x coins in 30 minutes, so its speed is x/30 coins/minute.
If we sum the speeds, we have that the speed will be:
speed = (x/15) + (x/30) = (2x + x)/30 = 3x/30 = x/10
The total speed can sort x/10 coins per minute, that is x coins in 10 minutes.
Answer:
N+F=42 & F+3N=70 System Solved: Natalie is 14 and Fred is 28
Step-by-step explanation:
Using variables N=natalies age and F=Freds age
N+F=42 ----> N=42-F (take this and plug it into the other equation)
F+3N=70 so F+3(42-F)=70 [simplify] F+126-3F=70 [further simplify]
-2F=-56 [divide -56 by -2] F=28 [then plug this number into the orig. equation]
So N+28=42 or N=14.
Answer:
B
Step-by-step explanation:
This quadratic factors.
x^2 - 15x + 56
= (x - 7)(x - 8)
x - 7 = 0
x = 7
=====
x - 8 = 0
x = 8
====
{7,8}
Difference = 48-19
= 29
production decrease = 29 × 100/ 48
= 60.41%
