Mathematics

Problem

This table describes the complaints received by a telecommunications ombudsman concerning internet services over a four year period.

Reason	2014/15	2015/16	2016/17	2017/18
Access	585	1127	2545	1612
Billing	1822	2102	3136	3582
Contracts	242	440	719	836
Credit control	3	44	118	136
Customer Service	12	282	1181	1940
Disconnection	n/a	n/a	n/a	248
Faults	86	79	120	384
Privacy	93	86	57	60
Provision	172	122	209	311
Total	3015	4282	8085	9109

Find the probability that a complaint received: a. in 2016/17 was about customer service b. at any time during the 4 year period was related to billing c. in 2017/18 did *not* relate to either billing or faults.

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