A person bought 17 gifts
for his nieces and nephews.
The gifts were dolls for the
nieces at $12.99 each, and
robots for the nephews at
$10.99 each. The total
spent was $198.83. How
many of each gift was
bought?
same concept as how I showed you on the other problem!
12.99(x)+10.99(17-x)=(198.83)(17)
The Mayan Empire, which ruled Central America for centuries, had two calendars. One calendar was the same
as ours, 365 days long (without leap year). The other calendar was 270 days long, the length of a woman's
pregnancy. If both start on day one at the same time, then after how many of our years will the two calendars
begin at day one at the same time again?
To find out how many dolls and robots were bought, we can set up a system of equations. Let's let "d" represent the number of dolls and "r" represent the number of robots.
Based on the given information, we know that the person bought a total of 17 gifts, so we can write the first equation as:
d + r = 17
Now let's consider the cost of the gifts. Each doll costs $12.99, so the cost of all the dolls can be represented as 12.99 times the number of dolls (d). Similarly, each robot costs $10.99, so the cost of all the robots can be represented as 10.99 times the number of robots (r). The total cost spent is $198.83, so we can set up the second equation as:
12.99d + 10.99r = 198.83
To solve this system of equations, we can use substitution or elimination method. Since the first equation is already solved for d, let's substitute d in the second equation:
12.99(17 - r) + 10.99r = 198.83
Now let's simplify this equation:
221.83 - 12.99r + 10.99r = 198.83
Combine like terms:
221.83 - 2r = 198.83
Subtract 221.83 from both sides:
-2r = -23
Divide both sides by -2:
r = 11.5
Now we have the number of robots, but since we can't have a fraction of a robot, we know that the person didn't buy half a robot. This means there must have been a mistake in the problem information or calculations.
Please check the given information again, or let me know if you have any other questions.