5+4v-v=1+3+5v
5+3v=4+5v
minus 3v both sides
5+3v-3v=4+5v-3v
5+0=4+2v
5=4+2v
minus 4 both sides
5-4=4-4+2v
1=0+2v
1=2v
divide both sides by 2
1/2=v
The number of situps form an AP with first term (a) = 17 and common difference (d) = 4
Tn = a + (n - 1)d
T12 = 17 + (12 - 1) x 4 = 17 + 11(4) = 17 + 44 = 61
Therefore, she will do 61 situps on day 12.
Answer:
A prime number is a natural number greater than 1 that cannot be formed by multiplying two smaller natural numbers.