Exams

Let the number of sides be n. 

The number of diagonals is given by ⁿC₂ - n  

^{Therefore, n}C₂ - n = 44, n>0 

ⁿC₂ - n = 44

n² - 3n - 88 = 0 

n² -11n + 8n - 88 = 0  

As n>0, n will not be -8. Therefore, n=11.

From the information provided we know that,

Principal + 8% p.a. interest on principal for n years = 180 …….. (1)

Principal + 4% p.a. interest on principal for n years = 120 ……… (2)

Subtracting equation (2) from equation (1), we get

4% p.a. interest on principal for n years = Rs.60.

Now, we can substitute this value in equation (2),

i.e Principal + 60 = 120

= Principal = Rs.60.

We know that SI = , where p is the principal, n the number of years and r the rate percent of  interest.

In equation (2), p = Rs.60, r = 4% p.a. and the simple interest = Rs.60.

Therefore, 60 =(60*n*4)/100

=> n = 100/4 = 25 years.

After 5 mins ..... 3 persons will get rumour
After 10 mins .... 3x2 + 3 = 9 = 32 persons will get
after 15 =5x3 min ......9x2 + 9 =27 = 33 persons will get news.
.
.
after 5x6 mins ... 36 = 729 persons will get news.

Therefore, time taken to spread the rumour to 729 persons is 30 minutes.

Since both 1 and 2 does not follow from the statement,so neither of them is implicit