10 Most Common 7th Grade OST Math Questions

B
Write the numbers in order:
\(2, 19, 28, 28, 35, 44, 67\)
Since we have 7 numbers (7 is odd), then the median is the number in the middle, which is 28.

C
Three times of 24,000 is 72,000. One-sixth of them canceled their tickets.
One sixth of 72,000 equals 12,000 \((\frac{1}{6}) × 72000 = 12000\).
60,000 \(72000 – 12000 = 60000\) fans are attending this week

A
It’s needed to have a ratio to find value of \(x\).
\(\frac{45}{40}=\frac{2x+4}{16}⇒ 40(2x+4)=45×16 ⇒ x=7\)

C
\(8 (4-(-8))=96\)

A
\(\frac{1}{3}x + \frac{1}{6}x + \frac{1}{4}x + 12= x\)
\((\frac{1}{3} + \frac{1}{6} + \frac{1}{4}) x+ 12= x\)
\((\frac{9}{12})x+ 12 = x\)
\(x = 48\)
In a bag of small balls \(\frac{1}{6}\) are white then: \(\frac{48}{6} = 8\)

B
Use the information provided in the question to draw the shape.
Use Pythagorean Theorem: \(a^2 + b^2 = c^2\)
\(40^2 + 30^2 = c^2 ⇒ 1600 + 900 = c^2 ⇒ 2500 = c^2 ⇒ c = 50\)

B
The question is this: 530.40 is what percent of 624?
Use percent formula:
\(part = \frac{percent}{100}× whole\)
\(530.40= \frac{percent}{100}× 624 ⇒ 530.40 = \frac{percent ×624}{100}⇒53040 = percent ×624\)
\(⇒percent = \frac{53040}{624}= 85\)
530.40 is \(85 \%\) of 624. Therefore, the discount is: \(100\% – 85\% = 15\%\)

B
If the score of Mia was 60, therefore the score of Ava is 30. Since the score of Emma was half as that of Ava, therefore, the score of Emma is 15.

D
If 17 balls are removed from the bag at random, there will be one ball in the bag.
The probability of choosing a brown ball is 1 out of 18. Therefore, the probability of not choosing a brown ball is 17 out of 18 and the probability of having not a brown ball after removing 17 balls is the same.

C
The weight of 12.2 meters of this rope is: \(12.2 × 600 \space g = 7320 \space g\)
\(1\space kg = 1000 \space g\) therefore,
\( 7320 \space g ÷ 1000 = 7.32 \space kg\)