There are 5 letters in the first row, 9 letters in the second row, and 13 letters in the third row on the whiteboard and so on. How many letters are there in 7th row? 30
29
28
27

29

Step-by-step explanation:

4*4=16+13=29

distance covered by pamela in 9 l of fuel = 99km

let us apply unitary method here.

distance covered by pamela in 1 l of fuel =99/9 =11 km

now let us find distance covered by pamela if she has 12 l of fuel.

distance covered in 12 l = distance covered in 1 l of fuel * 12

we know that distance covered by here in 1 l is 11 km.

so distance covered in 12 l of fuel = 11*12 = 132 km.