[填空题]
Charles has a New Years c0mmeyabv*0 jqqk f2jg4:i,y f4s8;xResolution that +- ah7aaz/jgy he wants to be able to complete 100 pushups in one go without a break. He sets out a 7aaj+/zha -gy training regime whereby he completes 20 pushups on the first day, then adds 5 pushups each day thereafter.
1.Write down the number of pushups Charles completes
1.1.on the 4th training day;
$u_4$= .
1.2.on the nth training day.
On the kth training day Charles completes 100 pushups for the first time.
2.Find the value of k.
k= .
3.Calculate the total number of pushups Charles completes on the first 10 training days.
$S_{10}$= .
Charles is also working on improving his long distance swimming in preparation for an Iron Man event in 12 weeks time. He swims a total of 10000 metres in the first week, and plans to increase this by 10 % each week up until the event.
4.Find the distance Charles swims in the 6th week of training.
$v_6$≈ .
5.Calculate the total distance Charles swims until the event.
$S_{12}$≈ m.
