Answer:

Step-by-step explanation:
Given,
Cost price of three thermos flask = 1080
Selling price of each thermos flask = 400
<u>Finding </u><u>the </u><u>selling </u><u>price </u><u>of </u><u>three </u><u>thermos </u><u>flask</u>
Since, the cost of 3 thermos flask is more than that of 1 thermos flask. So, the cost of 1 thermos flask is multiplied by 3 ( i.e 400 × 3 = 1200 )
Here, the selling price is greater than cost price.
So, there is profit.
And we know that,

⇒
⇒
Profit amount = 120
<u>Finding </u><u>the </u><u>profit </u><u>percentage</u>

⇒
⇒
Hope I helped!
Best regards!!
The picture isn’t clear enough
A1 = 4
a2 = 5a1 = 5 x 4 = 20
a3 = 5a2 = 5 x 20 = 100
a4 = 5a3 = 5 x 100 = 500
a5 = 5a4 = 5 x 500 = 2,500
Tn = ar^(n-1); where a = 4, r = 5
Tn = 4(5)^(n-1) = 4/5 (5)^n
Explicit formular is Tn = 4/5 (5)^n
Recursive formular is