i have question about this Introduction to Finance Case Study - Yates Motors

its part of book name - Financial for Non-financial for Managers by Pierre Bergerone, could you please help me with the part one two and three question thank you.

Part 1 : Questions: Example

1.What was the company's return on total assets last year? (2 marks)

2.How much cash will internal operations provide (i.e. what is generated by net income and changes in A/R, inventory etc.)? (3 marks)

3.How much will the company have to raise from external sources to continue with an investment of 950,000 in capital assets? (2 marks)

you just need to give types number two question do i have to break down the three display th changes in net income for prior year and next andd add them to get total cash ?

1. question ROA = Net income/ Total Asset

300,000/1,640,000= 18.29% ratio is this correct

2 question net income is 300,000

A/R 90,000

Inventory 400,000

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Total cash 790,000 <<<< is this correct or no ? for operation internal

3.avg a/r 160,000-90,000 =70,000

inventory next year 525000-inventory this year400,000 =125,000

790,000-125,000-70,000 = 595,000

950,000-595,000 = 355,000 to raise . is this correct please help me