An animal shelter spends $1.00 per day to care for each bird and $6.50 per day to care for each cat. Josiah noticed that the shelter spent $161.50 caring for birds and cats on Friday. Josiah found a record showing that there were a total of 46 birds and cats on Friday. How many birds were at the shelter on Friday?'

Let the number of birds be x and that of cats be y

The total number of animals will be:

x+y=46

⇒x=46-y

The total amount required for the caring will be:

x+6.5y=161.50

susbstituing the value of x in the above equation we get:

46-y+6.5y=161.50

solving for y we get:

5.5y=115.5

y=115.5/5.5

y=21

hence the number of cats is 21 cats, that of birds will be:

46-21=25 birds