Answer:
-18
Step-by-step explanation:
Find multiples of 30 and 40:
30: 30, 60, 90, 120, 150
40: 40, 80, 120, 160
The least common multiple is 120, so every 120 minutes they willl both ring.
1 hour = 60 minutes:
120/60 = 2 hours.
The bells ring together every 2 hours.
8 + 2 = 10 am
10 + = 12pm
12 + 2 = 2 pm
The bells will ring together at am, 12 pm and 2 pm.
Answer:

Step-by-step explanation:
The formula for the accrued amount from compound interest is

1. Amount in account on 1 Jan 2015
(a) Data:
a = £23 517.60
r = 2.5 %
n = 1
t = 1 yr
(b) Calculations:
r = 0.025

The amount that gathered interest was £22 944.00 but, before the interest started accruing, Carol had withdrawn £1000 from the account.
She must have had £23 944 in her account on 1 Jan 2015.
(2) Amount originally invested
(a) Data
A = £23 944.00

3. Summary
1 Jan 2014 P = £23 360.00
1 Jan 2015 A = 23 944.00
Withdrawal = <u> -1 000.00
</u>
P = 22 944.00
1 Jan 2016 A = £23 517.60
Let's imagine that we turn the machine on 100 times. (this will make the percent conversion easier)
the chance that works in the morning is 50% of 100 so it will work 50 times.
the chance that it will then continue for the rest of the day is 15% so 15%*50 (the number of times it worked), which is 7.5 times.
our times actually represented percent, so the answer is : 7.5%!