Question

Suppose you had d dollars in your bank account. You spent $12 but have at least $51 left. How much money did you have initially? Write and solve an inequality that represents this situation.

Answer 1

For this case we must raise an inequality.

We have "d" dollars initially and they are spent 12. Then:

`d-12`

At least 51 dollars remain, then, the sign of inequality is greater or equal in favor of the expression
`d-12`, that is:

`d-12\geq 51`

Resolving:

`d\geq 51 + 12\\d\geq 63`

There are at least 63 dollars left in the account.

Answer:

`d-12\geq 51\\d\geq 63`