Answer:
23 and 25
Step-by-step explanation:
x and x+2
x+3(x+2)=98
x+3x+6=98
4x=92
x=23
x+2=25
Answer:
9 times as many as 3 is 27.
Step-by-step explanation:
First term ,a=4 , common difference =4-7=-3, n =50
sum of first 50terms= (50/2)[2×4+(50-1)(-3)]
=25×[8+49]×-3
=25×57×-3
=25× -171
= -42925
derivation of the formula for the sum of n terms
Progression, S
S=a1+a2+a3+a4+...+an
S=a1+(a1+d)+(a1+2d)+(a1+3d)+...+[a1+(n−1)d] → Equation (1)
S=an+an−1+an−2+an−3+...+a1
S=an+(an−d)+(an−2d)+(an−3d)+...+[an−(n−1)d] → Equation (2)
Add Equations (1) and (2)
2S=(a1+an)+(a1+an)+(a1+an)+(a1+an)+...+(a1+an)
2S=n(a1+an)
S=n/2(a1+an)
Substitute an = a1 + (n - 1)d to the above equation, we have
S=n/2{a1+[a1+(n−1)d]}
S=n/2[2a1+(n−1)d]
Answer:
Step-by-step explanation:
Let x be gallons of 7%
Let y be gallons of 3%
364 = x + y
y = 364 - x
364(0.06) = x(0.07) + y(0.03)
364(6) = x(7) + y(3)
364(6) = 7x + 3y
364(6) = 7x + 3(364 - x)
364(6 - 3) = 7x - 3x
364(3) = 4x
x = 273
y = 364 - 273 = 91
273 gallons of 7%
91 gallons of 3%
