Answer:
# red marbles = 25
# blue marbles = 7
Step-by-step explanation:
r + b = 32
r = 4 + 3b
substitute '4 + 3b' for 'r' in the 1st equation
4 + 3b + b = 32
4 + 4b = 32
4b = 28
b = 7
red = 32 - 7
r = 25
Answer:
3135
Step-by-step explanation:
Givens
a1 = 6
Use t4 - t3 to get d
t4 = 27
t3 = 20
Step One
Find a1 and d
a1 = 6
d = t4 - t3
d = 27 - 20
d = 7
Step Two
Find the 30th Term
tn= a1 + (n -1 )*d
t30 = 6 + (30 - 1) * 7
t30 = 6 + 29*7
t30 = 6 + 203
t30 = 209
Step Three
Find the sum using Sum = (a + t30)*n/2
n = 30 given
a1 = 6 given
t30 = 209 calculated from step 2
Sum = (a1 + t30)*n/2 Substitute
Sum = (6+ 209)*30/2 Combine like terms and divide by 2
sum = 215 * 15 Multiply
Sum = 3135 Answer
Write the equation of the cost
p stands for the cost per pear, a stands for the cost per apple
6p + 3a = 3.9
2p + 5a = 3.3
Solve the equation system
To solve the equation system, we work on eliminating variable p so we will find the number of a. To eliminate, we have to change the coefficient of p to the same number (i will change it to coefficient 6)
6p + 3a = 3.9 (multiply 1)
2p + 5a = 3.3 (multiply 3)
---------------------------------
6p + 3a = 3.9
6p + 15a = 9.9
-------------------- - (substract)
-12a = -6
a = -6/-12
a = 0.5
To find the cost per pear, subtitute the number of a to one of the equation
2p + 5a = 3.3
2p + 5(0.5) = 3.3
2p + 2.5 = 3.3
2p = 3.3 - 2.5
2p = 0.8
p = 0.4
The cost of one pear is $0.4
