Akosua received the first of an annual birthday gift of money from her uncle on her 10th birthday celebration. This gift of cash was GHC60.00 and on each subsequent birthday the gift was GH¢15.00 more...

Akosua received the first of an annual birthday gift of money from her uncle on her 10th birthday celebration. This gift of cash was GHC60.00 and on each subsequent birthday the gift was GH¢15.00 more than the year before. The amounts of these gifts form an arithmetic sequence like we have in series and sequence mathematical concept. Show that, immediately after her 12th birthday celebration, the total of these gifts amounted to GH¢225.00 After Akosua had received n of these birthday gifts, the total money that she had received from these gifts was GH¢3,375.00, show that n+7n = 450 ? Find the value of n above and determine Akosua's age at this time?