mr.mancho my great dane ate 125 hot dogs over a five day period. each day he ate seven more hot dogs than on the previous day. how many hot dogs did he eat on the first day.....

Read DrWLS's explanation carefully.

http://www.jiskha.com/display.cgi?id=1287095215

You need to use the strategy of working backwards

day 5= 125 hot dogs
day 4= 125-7=???
day 3= ???-7 etc.
day 2=
day 1=

To find out how many hot dogs the Great Dane ate on the first day, we need to work backwards and figure out the pattern of increasing hot dog consumption.

Let's start by setting up an equation:
Let x represent the number of hot dogs eaten on the first day.

On the second day, the Great Dane ate x + 7 hot dogs.
On the third day, the Great Dane ate (x + 7) + 7 hot dogs, which simplifies to x + 14.
On the fourth day, the Great Dane ate (x + 14) + 7 hot dogs, which simplifies to x + 21.
On the fifth day, the Great Dane ate (x + 21) + 7 hot dogs, which simplifies to x + 28.

Now, let's add up the total number of hot dogs consumed over the five-day period:
x + (x + 7) + (x + 14) + (x + 21) + (x + 28) = 125

Reducing the equation:
5x + 70 = 125

Subtracting 70 from both sides:
5x = 55

Dividing both sides by 5:
x = 11

Therefore, the Great Dane ate 11 hot dogs on the first day.