Answer:
0.7518
Step-by-step explanation:
Just plz trust me
General formula for n-th term of arithmetical progression is
a(n)=a(1)+d(n-1).
For 3d term we have
a(3)=a(1) +d(3-1), where a(3)=7
7=a(1)+2d
For 7th term we have
a(7)=a(1) +d(7-1)
a(7)=a(1) + 6d
Also, we have that the <span>seventh term is 2 more than 3 times the third term,
a(7)=3*a(3)+2= 3*7+2=21+2=23
So we have, </span>a(7)=a(1) + 6d and a(7)=23. We can write
23=a(1) + 6d.
Now we can write a system of equations
23=a(1) + 6d
<span> - (7=a(1)+2d)
</span>16 = 4d
d=4,
7=a(1)+2d
7=a(1)+2*4
a(1)=7-8=-1
a(1)= - 1
First term a(1)=-1, common difference d=4.
Sum of the 20 first terms is
S=20 * (a(1)+a(20))/2
a(1)=-1
a(n)=a(1)+d(n-1)
a(20) = -1+4(20-1)=-1+4*19=75
S=20 * (-1+75)/2=74*10=740
Sum of 20 first terms is 740.
Answer:
₹ 81.75
Step-by-step explanation:
Total = ₹ 120.
He bought one book for ₹ 25.75 and a pen for ₹ 12.50.
₹ 25.75 + ₹ 12.50 = ₹ 38.25
How much money does he have now?
₹ 120 - ₹ 38.25 = ₹ 81.75
A=p(1+i/m)^mn
P=3000
i=0.20
M=12
n=1/12
A=3,000×(1+0.20÷12)^(12*1/12)
=3,050
Interest earned=3050-3000=50
