Question

elva monitors her savings account online. on monday she withdraws money, and the change to her account balance is −$51.25. on tuesday she deposits money and the change to her balance is +$39.50. she wants to know the total change in her account after the two transactions. write an expression for the total change in elvas account. −51.25 + 39.50 which amount is the best approximation of the total change in elvas account balance? −$10 −$20 −$90 −$80

Explanation:

Step1: Calculate the exact total change

To find the total change, we use the expression \(-51.25 + 39.50\). Let's compute this:
\(-51.25+39.50 =-(51.25 - 39.50)= - 11.75\)

Step2: Approximate the result

Now we need to find the best approximation from the given options. The value we got is \(-11.75\), which is closest to \(-\$10\)? Wait, no, wait. Wait, \(-51.25\) is approximately \(-50\) and \(39.50\) is approximately \(40\). So \(-50 + 40=-10\)? Wait, but our exact calculation was \(-11.75\). Wait, maybe I made a mistake in approximation. Wait, \(-51.25\) is about \(-50\) (rounding to nearest ten) and \(39.50\) is about \(40\). So \(-50+40 = - 10\). But wait, the options are \(-\$10\), \(-\$20\), \(-\$90\), \(-\$80\). Wait, but let's check again. Wait, \(-51.25+39.50=-11.75\), which is approximately \(-10\)? But wait, maybe the problem expects a different approximation. Wait, no, \(-51.25\) is closer to \(-50\) and \(39.50\) is closer to \(40\), so \(-50 + 40=-10\). But wait, the exact value is \(-11.75\), which is very close to \(-10\). But wait, maybe I miscalculated. Wait, no, \(-51.25+39.50\): \(51.25 - 39.50 = 11.75\), so with the negative sign, it's \(-11.75\). So the closest approximation from the options is \(-\$10\)? Wait, but let's check the options again. The options are \(-\$10\), \(-\$20\), \(-\$90\), \(-\$80\). So \(-11.75\) is closest to \(-10\). But wait, maybe the problem has a typo? Wait, no, let's re - evaluate. Wait, maybe the initial numbers: \(-51.25\) and \(+39.50\). Let's do the addition: \(-51.25+39.50=-11.75\), which is approximately \(-10\). So the best approximation is \(-\$10\)? Wait, but let's check the options. The first option is \(-\$10\), second is \(-\$20\), etc. So the best approximation is \(-\$10\)? Wait, but maybe I made a mistake. Wait, no, \(-11.75\) is very close to \(-10\). So the best approximation is \(-\$10\).

Wait, but wait, maybe the problem is designed to have \(-51.25\) approximated as \(-50\) and \(39.50\) as \(40\), so \(-50 + 40=-10\). So the answer should be \(-\$10\).

Answer:

The best approximation of the total change in Elva's account balance is \(\boldsymbol{-\$10}\) (the first option: \(-\$10\)).