There is a custom field total in account. I want to update field value with the sum of previous record total value and new record total record value if they have same industry and record type

There are two record types in account. using Trigger I'm populating account industry field from record type 1 to record type 2 Now I want to make account industry as read only field in record type2

 The requirement is I've two record types in contact one is new contact and another is renewal contact. I've created a contact whose record type is new contact and again I've created a record with record type renewal contact. the common field linking these two records is account. If the account is same for two records then I want to get same values of certain section in  record with recordtype in record which of record type renewal same as values of record type with new contact. please write the trigger helper and handler.

I have a record in account with billing city pune. Now I want to create a record with billing city pune but account information section values should be updated with previous record values whose billing city is pune. how I can achieve it
 

Account 'Abc' has 3 contacts. In two contact records phone number is empty  but in third contact phone number is not empty. The third contact phone number should be updated in other two records phone numbers.

Create a vf page for account with name and phone as input fields, create submit button on that page . After giving the input values if we click the submit button if the record is the duplicate record then it should redirect to edit mode of the page.If it is new record then insert the record and redirect  to edit mode of that record. 

There is a custom field total in account. I want to update field value with the sum of previous record total value and new record total record value if they have same industry and record type

I have a record in account with billing city pune. Now I want to create a record with billing city pune but account information section values should be updated with previous record values whose billing city is pune. how I can achieve it
 

Can anyone explain what approach to use for solving this.
what custom object is required and what fields?

DreamForce is A global consulting agency and proven strategic partner to build mobile solutions. They have a requirement to build a mobile app using SF1 for field service management where the maintenance & repair activity happens at customer’s location. Customer should be able to submit a job request, the form should capture all the required details about a job request. He should be able to log, track & update the job request. The follow up task need to be created for a manager once the job request is submitted. Manager should be able to see a report which will indicate the total revenue generated in a month & a dashboard for the request fixed in a month.

Map<String, map<String, Integer>> ratingVsRecordCountMapOfmap = new Map<String, map<String, Integer>>();
List<Task> lstAggResult = [Select Priority, Status From Task Where Priority != Null AND Status != Null];
if(!lstAggResult.isEmpty()) {
 for(Task objTest : lstAggResult) {
       if(ratingVsRecordCountMapOfmap.containsKey(objTest.Priority)) {
            Map<String, Integer> innermap = ratingVsRecordCountMapOfmap.get(objTest.Priority);
            //if(!innermap.isEmpty()) {
                if(innermap.containsKey(objTest.Status)) {
                   Integer count = innermap.get(objTest.Status) + 1;
                  innermap.put(objTest.Status, count);
               }
               else {
                   innermap.put(objTest.Status, 1);
               }
               ratingVsRecordCountMapOfmap.put(objTest.Priority, innermap);
           //}
        }
       else {
            Map<String, Integer> innermap = new Map<String, Integer>();
            innermap.put(objTest.Status, 1);
            ratingVsRecordCountMapOfmap.put(objTest.Priority, innermap);
       }
    }
}
system.debug('---> ' + ratingVsRecordCountMapOfmap);

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Like this I want to display in table

Populate the comma separated related Contact name on Account Description field which should work for insert, update and delete case.