Answer:176 psychology textbooks and 98 Biology textbooks were sold.
Step-by-step explanation:
Let x represent the number of psychology textbooks that were sold.
Let y represent the number of biology textbooks that were sold.
textbook store sold a combined total of 274 psychology and biology textbooks in a week. This means that
x + y = 274 - - - - - - - - - - -1
The number of psychology textbooks sold was 78 more than the number of biology textbooks sold. This means that
x = y + 78
Substituting x = y + 78 into equation 1, it becomes
y + 78 + y = 274
2y = 274 - 78
2y = 196
y = 98
x = y + 78 = 98 + 78
x = 176
338.50 - 45 = 293.50 was spent on tolls
293.50 / 14 = 20.96
so 21 tolls
Answer:
Step-by-step explanation:
3a-8a>-20
-5a>-20
a>-20/-5
a>4
Answer:
<em>t = 1.51</em>
Step-by-step explanation:
<u>Exponential Model</u>
The exponential model is often used to simulate the behavior of a magnitude that either grow or decay in proportion to the existing amount of that magnitude.
The model can be expressed as
In this case, Mo is the initial mass of the radioactive substance and k is a constant which value is positive if the mass is growing or negative if the mass is decaying.
The value of k is not precisely given in the question, we are assuming
The model is now
We are required to compute the time it takes the mass to reach one-half of its initial value:
Simplifying
Taking logarithms
Solving for t
Answer: The distance in the map is 19 inches.
Step-by-step explanation:
On the map. 2 inches represent an actual distance of 64 miles.
The actual distance between town A and town B is equal to 608 miles, we need to divide this distance into groups of 64 miles.
N = 608/64 = 9.5
And each one of those 9.5 groups is represented with 2 inches in the map, then the distance in the map is:
d = 9.5*2 inches = 19 inches.