The phrase "a manageable one" is correct and usable in written English.
It can be used to describe something that is easy to handle or control, often in the context of tasks, projects, or challenges.
Example: "The project seemed daunting at first, but after breaking it down into smaller parts, it became a manageable one."
Alternatives: "an achievable task" or "a feasible option."
A manager, by using quantitative techniques can change a complicated problem into a manageable one.
War finance was efficiently managed, and although Henry died in debt, the level was a manageable one.
It strikes us as easier and wiser to proceed step by step toward broad legalization, starting with marijuana, moving on to heroin (a minor trade in Mexico, and a manageable one stateside) and dealing only later, when Washington and others are ready, with cocaine and synthetic drugs.
The producers of Q&A believed it was perfectly reasonable to allow the former terrorism suspect Zaky Mallah to appear on the live talk show – a risk given his background, but a manageable one.
It wasn't exactly a modest portfolio, but it was certainly a manageable one.
"For those of you still in the market for a New Year's resolution, here's a manageable one: Get yourself to...see Kristen Kosmas's new play, There There.
[Lee Kuan Yew] may be the single best available volume for those who want a quick grasp of Lee's thinking on foreign affairs and geopolitics....in compiling such a rich collection of statements on such a wide range of global issues, Allison and Blackwill have done both scholars and general readers a service by providing a manageable, one-stop shop on Lee's thinking.
India's external debt is a manageable one-fifth of GDP, and little of it is short-term.Nor has the rupee fared badly against currencies other than the dollar.
"Discover Indonesia" (Smithsonian/ Folkways) edits all the diversity into a manageable one-CD sampler that includes music from gongs, guitars, brass band, bamboo and singers whose voices invoke Asia, the Middle East and nameless spirits.
Mrs. Felsher took on her school board role after she had switched from her partner job to a more manageable one as an in-house corporate counsel.
Given these discouraging results, even for an extremely small data set, it was clear that an alternative approach or a redefinition of the problem to a more manageable one was in order.
