<p>Following is a medium level math problem which I got the answer but not sure if I did it right or wrong coz' I kinda got confused.</p>
<p>11) Square tiles measuring 1/2 foot by 1/2 foot are sold in boxes containing 10 tiles each. What's the least number of boxes of tiles needed to cover a rectangular floor that has dimensions 12 feet by 13 feet?</p>
<p>A) 7
B) 16
C) 32
D) 57
E) 63</p>
<p>Thanks in advance :)</p>
<p>Wherever you got this question should tell you the answer</p>
<p>each tile is 1/2X1/2=1/4 sq ft=0.25 sq ft, each box contains 0.25X10=2.5 sq ft
the area of the floor is 12X 13=156 sq ft
the number of box needed =156/2.5=62.4 boxes
round to 63 boxes.</p>
<p>I know the answer already. I just want to know how others would solve this kind of problem. Btw, B is not the answer.</p>
<p>@ wildwood888 yeah, that’s the correct answer. I did exactly the same, so I got 62.5 and was wondering because it’s not the exact number coz we usually have to round on grid-ins, not on the multiple choice questions. Right.</p>
<p>@ wildwood888 Thank you so much, btw.</p>
<p>When the number required is referring to people, boxes, tiles, buildings etc, you always have to round it to the nearest whole number.</p>
<p>When the number required is referring to the average or so, it is not rounded.</p>
<p>There are two reasons to round an answer:</p>
<ol>
<li><p>They explicitly tell you to round your answer to the nearest whatever. In that case, you follow the standard rules for rounding (5 or more rounds up)</p></li>
<li><p>You are calculating how many fixed-sized packages you need to have enough of whatever. In this case, you always round up. So for example, if in this problem, even if the answer had come out to 62.1 boxes, you would still have to round up to 63 so that you would have enough tiles.</p></li>
</ol>
<p>I simply just saw that each tile was 1/2 feet by 1/2 feet. To fill a 12 by 13 rectangle you would need 24 1/2 ft tiles for the length and 26 1/2 ft tiles for the width. Multiply the two together to find the total number of tiles in the rectangle and you get 624. Divide by 10 and get 62.4 boxes then round up to 63.</p>
<p>Basic Geometry SAT Strategy: To see how many two-dimensional objects fit inside another two-dimensional object we divide areas. </p>
<p>(12<em>13)/(.5</em>.5) = 624 (just use your calculator here).</p>
<p>Since there are 10 in a box, divide by 10 to get 62.4. </p>
<p>Since you can’t have a fractional part of a box you need 63 boxes.</p>
<p>Important Note: We do not round the answer here. Rounding would give 62 which is incorrect. We have to move up to 63 otherwise we will not have enough boxes!</p>