Question

decimal percent of a whole
score: 4/10 penalty: none
question
find 24.7% of 169. round to the nearest tenth.
answer attempt 1 out of 2

Explanation:

Step1: Convert percent to decimal

To find a percentage of a number, first convert the percentage to a decimal by dividing by 100. So, \( 24.7\% = \frac{24.7}{100} = 0.247 \).

Step2: Multiply by the whole number

Now, multiply this decimal by 169. So, \( 0.247 \times 169 \). Let's calculate that: \( 0.247\times169 = 0.247\times(170 - 1)=0.247\times170 - 0.247\times1 = 41.99 - 0.247 = 41.743 \).

Step3: Round to nearest tenth

The number 41.743 rounded to the nearest tenth. The tenths place is 7, the hundredths place is 4, which is less than 5, so we keep the tenths place as is. So, 41.7 (wait, no, wait: 41.743, tenths digit is 7, hundredths is 4, so when rounding to nearest tenth, look at hundredths. 4 < 5, so we round down? Wait, no, 41.743: the tenths place is 7, the number after is 4, so 41.7? Wait, no, wait, 0.247169: let's recalculate 0.247169. 1690.2 = 33.8, 1690.04 = 6.76, 1690.007 = 1.183. Then add them: 33.8 + 6.76 = 40.56 + 1.183 = 41.743. Now, rounding 41.743 to the nearest tenth: the tenths digit is 7, the hundredths digit is 4, which is less than 5, so we round down? Wait, no, 41.743: the tenths place is 7, the number is 41.743. So to the nearest tenth, we look at the hundredths place (4). Since 4 < 5, we don't round up the tenths place. So 41.7? Wait, but wait, 41.743: the tenths digit is 7, the next digit is 4, so 41.7. Wait, but let me check again. Wait, 0.247169: 169247/1000. 169247: let's calculate 170247 = 41990, minus 1247 = 247, so 41990 - 247 = 41743. Then divide by 1000: 41743/1000 = 41.743. Now, rounding to the nearest tenth: the tenths place is 7, the hundredths place is 4, so we round to 41.7? Wait, no, wait, 41.743: the tenths digit is 7, the number after the tenths is 43 (hundredths and thousandths). So when rounding to the nearest tenth, we look at the hundredths digit (4). Since 4 < 5, we keep the tenths digit as 7, so 41.7. Wait, but wait, maybe I made a mistake in calculation. Wait, 0.247169: let's do 1690.247. 1690.2 = 33.8, 1690.04 = 6.76, 1690.007 = 1.183. Adding those: 33.8 + 6.76 = 40.56 + 1.183 = 41.743. Yes, that's correct. So rounding 41.743 to the nearest tenth: the tenths place is 7, the hundredths is 4, so 41.7. Wait, but wait, 41.743: the tenths digit is 7, the number is 41.743. So to the nearest tenth, it's 41.7? Wait, no, wait, 41.743: the tenths place is 7, the next digit is 4, so we round down, so 41.7. But wait, maybe I miscalculated the multiplication. Let me check with another method. 1690.247: 0.247100 = 24.7, 0.24760 = 14.82, 0.247*9 = 2.223. Then 24.7 + 14.82 = 39.52 + 2.223 = 41.743. Yep, same result. So rounding to the nearest tenth: 41.7. Wait, but wait, 41.743: the tenths digit is 7, the hundredths is 4, so 41.7. But wait, maybe I made a mistake in the rounding. Wait, the rule is: look at the digit to the right of the place you're rounding to (tenths place, so look at hundredths place). If that digit is 5 or more, round up the tenths place; if less than 5, leave it. So 4 is less than 5, so tenths place remains 7, so 41.7.

Answer:

41.7