Able Able

He counts from 13.

It means 13 is the 1st number he says.

So, he has to say 10 more numbers.

He adds 7 in each.

So, 10 X 7 = 70

Now, add 70 to 13.

70 + 13=

                                  83

a=13, d=7 we have to find the 11th term of this AP. a11=a+(n-1)d. Using this we get a11=83

He starts counting by 13 and conts by 7 So, 13+7=20 20+7=34 34+7=41 41+7=48 48+7=55 55+7=62 62+7=69 69+7=76 76+7=83 83, is the 11th no.

13 is the first number, and 7 X 10 = 70, and 13+70= 85

1st : 13 next 10 increment by 7 : 7x10 = 70 11th = 13+70 = 83

The first term in the series is 13.We should count by 7.So the numbers in the series are-

First=13

Second=20

Third=27

And after tenth term the eleventh term is 83.We can do this by the following equation.13+7*{11-1].

13 + ( 7 * (11-1) ) = 83

It's very simple with 10 number apart 7 is 7 . 10 = 70, and then we have 70 + 13 = 83. 13 is the first number => 83 is 11th number

13+(7*10) =83

Un = a + (n-1)b

U11 = 13 + (11-1) 7

U11 = 13 + 70

U11 = 83

Able started counting and it became as under 13, 20, 27 ............ and it is an arithmetic progression so
its 11th can be determined as 11th term =13+(11-1)(7)=13+10(7)=13+70= 83

Able will Count 13, 20 , 27 , .... for this you can use this formula : Un = a + (n-1)b . 1. n = the number that you searching for 2. a is the first number that has been counted by Able, so a = the first number from a data 3. b is the difference between the second data and the first data, Example : 2,4,6,8. the b is -> 4 -2 = 2 or 6 - 4 = 2 or 8 - 6 = 2. For more questions about this formula just ask me, or maybe you can search the internet. Answer a = 13 n = 11 b = 7 Answer : 13 + ( 11 - 1 ) \times 7 = 13 + 10 \times 7 = 13 + 70 = 83

The numbers Able says forms an A.P. : 13, 20, 27, ...

We need what is the 11th number in the sequence. Here, $a=13, d=7, n=11$ . So, $a_{11}=13+10\times7 = 13+70 = \boxed{83}$

The 1st number is 13. So the 11th number would be $13+7*(11-1) = \boxed{83}$