Solve the following math problems: 1. One morning, Marcia works from 08:20 to 11:15. Find how long she works for. Give your answer in hours and minutes. 2. Expand: 7(x-8) 3. Here... Solve the following math problems: 1. One morning, Marcia works from 08:20 to 11:15. Find how long she works for. Give your answer in hours and minutes. 2. Expand: 7(x-8) 3. Here is a sequence: a, 13, 9, 3, -5, -15, b, ... Find the value of a and the value of b. 4. Complete these statements: (a) When w= ..., 10w = 70. (b) When 5x = 15, 12x = ... 5. Given the numbers 22, 17, 25, 41, 39, 4, work out the difference between the two prime numbers in the list above.
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Understand the Problem
The user has provided an image of a math worksheet consisting of 5 problems. The problems cover topics such as calculating the duration between two times, expanding algebraic expressions, identifying patterns in sequences, solving simple equations, and identifying prime numbers.
Answer
1. 2 h 55 min 2. $7x - 56$ 3. $a = 15$, $b = -27$ 4. a) $w = 7$ b) $12x = 36$ 5. 24
Answer for screen readers
- 2 h 55 min
- $7x - 56$
- $a = 15$, $b = -27$
- a) $w = 7$ b) $12x = 36$
- 24
Steps to Solve
- Calculate the duration between 08:20 and 11:15
To find the duration, subtract the start time from the end time.
Hours: $11 - 8 = 3$ hours Minutes: $15 - 20 = -5$ minutes
Since we have negative minutes, we need to borrow an hour from the 3 hours, converting it into minutes.
1 hour = 60 minutes, so we now have 2 hours and $60 - 5 = 55$ minutes.
- Expand the expression $7(x - 8)$
Distribute the 7 to both terms inside the parentheses: $7 * x - 7 * 8 = 7x - 56$
- Find the values of a and b in the sequence
The sequence is: $a, 13, 9, 3, -5, -15, b$
The difference between consecutive terms is: $13 - 9 = 4$ $9 - 3 = 6$ $3 - (-5) = 8$ $-5 - (-15) = 10$
The differences are increasing by 2 each time (4, 6, 8, 10). So, the next difference should be 12.
To find $b$, subtract 12 from -15: $b = -15 - 12 = -27$
To find $a$, we need to go backwards in the sequence. The difference before the '4' must have been 2. Thus $a - 13 = 2$, so $a = 13 + 2 = 15$.
- Complete the statements
(a) $10w = 70$ Divide both sides by 10 to find $w$. $w = 70 / 10 = 7$
(b) $5x = 15$ First, solve for $x$: $x = 15 / 5 = 3$ Now, substitute $x = 3$ into $12x$: $12x = 12 * 3 = 36$
- Find the difference between the two prime numbers
The list of numbers is: 22, 17, 25, 41, 39, 4 Prime numbers are numbers that have only two distinct factors: 1 and themselves. The prime numbers in the list are 17 and 41.
The difference between 41 and 17 is: $41 - 17 = 24$
- 2 h 55 min
- $7x - 56$
- $a = 15$, $b = -27$
- a) $w = 7$ b) $12x = 36$
- 24
More Information
A prime number is a natural number greater than 1 that is not a product of two smaller natural numbers. A natural number greater than 1 that is not prime is called a composite number.
Tips
- When calculating time durations, forgetting to borrow an hour (60 minutes) if the minutes subtraction results in a negative value is a common mistake.
- For the sequence, not recognizing the pattern in the differences between the terms can lead to an incorrect calculation of a and b.
- Forgetting to solve for $x$ before substituting it into $12x$ in question 4 (b).
- Confusing composite and prime numbers
- When expanding, forgetting to multiply both terms in parenthesis
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