Answer:
25 < t < 350
Step-by-step explanation:
The mean lifetime of a bulb ranges from 25 to 350 hrs but the question is unclear.
Answer:
10 tapes and 6 Cds
Step-by-step explanation:
As tapes sell for $10 and CD sell for $15, let t be the number of tapes bought and c the number of cds, we can write an equation for the expenditure in the form:
10c + 16t = expenditure
We also n=know she spent 220, so:
10c + 16t = 220
As she bought 16 items, the sum of CD and tapes must be equal to 16. So:
c + t = 16
If we take this last equation and subtract t in both sides:
c = 16 - t
We got the number of CD depending on the number of tapes. We can replace this in the first equation to get t:
10 [16 - t] + 16t = 220
160 - 10 t +16t = 220
160 + 6t = 220
If we subtract 160 in both sides
6t = 220 - 160
6t = 60
Dividing both by 6:
t = 60/6 = 10
So, she purchased 10 tapes. As in total she purchased 16 items she must have purchased 6 cds.
Solution: She purchased 10 tapes and 6 CDs
Answer:
x=1, y=4
Step-by-step explanation:
x+y=5 - (1)
y=3x + 1 (2)
Sub (2) into (1)
x + (3x +1)=5
4x=5-1
x=4 ÷4
=1
Sub x=1 into (2)
y=3(1)+1
= 4
