Math Problem Statement

dela2023.pdf

532.27 KB

solve the exercises

Solution

Let's work through the exercises step by step.

1. Solve the expression:

A=10(62.831.4+1)3532A = 10 \cdot \left( \frac{62.8}{31.4} + 1 \right)^3 - 53 \cdot 2

First, calculate 62.831.4=2\frac{62.8}{31.4} = 2, so the expression inside the parentheses becomes: 2+1=32 + 1 = 3

Now cube 3: 33=273^3 = 27

So the expression becomes: A=1027532=270106=164A = 10 \cdot 27 - 53 \cdot 2 = 270 - 106 = 164

Thus, A=164A = 164.


2. Solve the expression:

416025(5314)\frac{41}{60} - \frac{2}{5} \cdot \left( \frac{5}{3} - \frac{1}{4} \right)

First, simplify 5314\frac{5}{3} - \frac{1}{4} by finding a common denominator: 5314=2012312=1712\frac{5}{3} - \frac{1}{4} = \frac{20}{12} - \frac{3}{12} = \frac{17}{12}

Now multiply 251712\frac{2}{5} \cdot \frac{17}{12}: 251712=3460\frac{2}{5} \cdot \frac{17}{12} = \frac{34}{60}

Now subtract: 41603460=760\frac{41}{60} - \frac{34}{60} = \frac{7}{60}

Thus, the result is 760\frac{7}{60}.


3. Solve the following:

(a) 13.5551:0.00113.5551 : 0.001 13.5551÷0.001=13555.113.5551 \div 0.001 = 13555.1

(b) 0.020231050.02023 \cdot 10^5 0.02023100000=20230.02023 \cdot 100000 = 2023


4. Find which numbers are divisible by 2, 3, and 5:

1465, 60120, 42040, 520500

A number divisible by 2, 3, and 5 must be divisible by 30 (since 235=302 \cdot 3 \cdot 5 = 30).

  • 1465: Not divisible by 2, so it's not divisible by 30.
  • 60120: Divisible by 2, 3, and 5 (divisible by 30).
  • 42040: Divisible by 2 and 5, but not by 3.
  • 520500: Divisible by 2, 3, and 5 (divisible by 30).

Thus, the numbers are 60120 and 520500.


5. Calculate the printing costs:

(a) Cost of printing 80 photos: 800.17=13.6080 \cdot 0.17 = 13.60 \, \text{€}

(b) Cost of printing 120 photos: The first 100 photos cost 1000.17=17100 \cdot 0.17 = 17 \, \text{€}, and the remaining 20 photos cost 200.15=320 \cdot 0.15 = 3 \, \text{€}. 17+3=2017 + 3 = 20 \, \text{€}

(c) Maximum number of photos with 32.5€: The first 100 photos cost 17€. The remaining budget is: 32.517=15.532.5 - 17 = 15.5 \, \text{€} For each additional photo, the cost is 0.15€, so: 15.50.15=103.33\frac{15.5}{0.15} = 103.33 Thus, you can print 100 + 103 = 203 photos.


6. Solve the pricing problem:

(a) After a reduction of 15\frac{1}{5}, the new price is: 1501505=15030=120150 - \frac{150}{5} = 150 - 30 = 120 \, \text{€} After adding 36€: 120+36=156120 + 36 = 156 \, \text{€}

(b) The percentage increase from the original price: 156150150100=6150100=4%\frac{156 - 150}{150} \cdot 100 = \frac{6}{150} \cdot 100 = 4\%


7. Maximum number of children sharing chocolates, candies, and lollipops:

You need to find the greatest common divisor (GCD) of 30, 42, and 12: GCD(30,42,12)=6\text{GCD}(30, 42, 12) = 6 Thus, at most 6 children can equally share the treats.


8. Time to fill the tank with both taps:

The first tap fills the tank in 8 hours, so it fills 18\frac{1}{8} of the tank per hour. The second tap empties 110\frac{1}{10} of the tank per hour.

The net filling rate is: 18110=540440=140\frac{1}{8} - \frac{1}{10} = \frac{5}{40} - \frac{4}{40} = \frac{1}{40} Thus, the tank will fill in 40 hours.


Let me know if you need further details or clarifications!

Here are some related questions:

  1. How would the result change if the second tap emptied faster?
  2. What if the price increase in Exercise 6 was 50€ instead of 36€?
  3. How can we find divisibility for numbers other than 2, 3, and 5?
  4. Can you explain the process of finding the GCD in Exercise 7 in detail?
  5. How would the printing costs change with different rates for photos?

Tip: For mixed operations, always simplify expressions step by step, starting with parentheses and exponents.

Ask a new question for Free

By Image

Drop file here or Click Here to upload

Math Problem Analysis

Mathematical Concepts

Algebra
Arithmetic
Division
Multiplication
Fractions
Percentages

Formulas

Basic arithmetic operations
Greatest common divisor
Fraction operations
Rate of work formula

Theorems

Divisibility rules for 2, 3, and 5

Suitable Grade Level

Grades 7-9