Can someone help please

3a. (i). Sequence is in Arithematic

(ii). Sequence is in Geometric

3b. 2520 Sum of First 20 Arithmetic Sequence

3c. 98292 Sum of First 13 Geometric Sequence

Step-by-step explanation:

According to the Question,

3a. (i) Arithmetic Sequence () = 12 , 24 , 36 , 48 .....

it is a sequence of numbers such that the difference between the consecutive terms is same. example → 24+12=12 , 36-24=12 , 48-36=12 ∵Common Difference=12

(ii) Geometric Sequence () = 12 , 24 , 48 , 96 .....

A geometric series is a series for which the ratio of each two consecutive terms is a constant function. example → 24/12= 2 , 48/24= 2 , 96/48= 2 ∵Common Ratio=2

3b. Sum of first 20 terms of Arithematic sequence,

(Where, a=first term of sequence , n= number of term & d=common difference)

=10[2×12 + 19×12]

=10×252  ⇔  2520

3c. Sum Of First 13 term of a geometric sequence,

(Where, a=first term of sequence , n= number of term & r= common ratio)

=12(-1) / 2-1

=12×8191  ⇔  98292

hello,

b) 62.47% of the students are between 14 and 18 years old.

step-by-step explanation:

mean = 15 and standard deviation = 2

student between 14 to 18

formula used z-score

for age 14 , z score

using z-table , p(z> -0.5)=0.3085

for age 18 , z score

using z-table , p(z< 1.5)=0.9332

p(-0.5< z< 1.5)=0.9332-0.3085 = 0.6247

thus, 62.47% of the students are between 14 and 18 years old.

click to let others know, how is it

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